Methods for treating ovarian cancer, poly (phosphoester) compositions, and biodegradable articles for same

ABSTRACT

Biodegradable polymer compositions suitable for intraperitoneal administration to treat a mammalian subject having ovarian cancer are described, wherein the polymer compositions provide extended release of the antineoplastic agent into the peritoneum of the subject. The subject compositions can increase the median survival rate from the cancer by at least about 10%, as compared with the median survival rate obtained by administration of a composition comprising the same dosage of the antineoplastic agent without the biodegradable polymer. Solid articles and methods for treating ovarian cancer are also described.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to methods for treating ovariancancer, in particular those pertaining to the extended release of anantineoplastic agent from biodegradable poly(phosphoester) compositions.

[0003] 2. Description of the Prior Art

[0004] Antineoplastic agents, such as paclitaxel, have sometimes beenused to treat ovarian cancer. For example, those in the art haveattempted to administer paclitaxel in normal saline by infusion into theperitoneal cavity of women having ovarian cancer as a prolonged seriesof weekly treatments. Francis et al., “Phase I Feasibility andPharmacologic Study of Weekly Intraperitoneal Paclitaxel: A GynecologicOncology Group Pilot Study”, J. of Clinical Oncology. 13:12, 2961-67(1995). However, problems with multiple toxicities, such as abdominalpain, nausea, vomiting, leukopenia, and fatigue, are often encounteredwith the high fluid volumes and drug dosages required for efficacy withthis approach. Further, the repeated dosing and attendant discomfort isoften inconvenient and, sometimes, even unacceptable for patients.

[0005] Thus, there exists a need for a method of effecting the in vivo,controlled release of a variety of different antineoplastic agents intothe peritoneum, whether they are small hydrophobic drugs, such aspaclitaxel, or large and bulky bio-macromolecules, such astherapeutically useful proteins. Preferably, effective release of theantineoplastic agent should occur without requiring the presence ofsignificant amounts of a physiologically acceptable fluid vehicle, suchas normal saline or an organic solvent. There is also a continuing needfor biodegradable polymer compositions that may provide extended releasein such a way that trauma to the surrounding soft tissues can beminimized.

[0006] Biocompatible polymeric materials have been used in varioustherapeutic drug delivery and medical implant applications. If a medicalimplant is intended for use as a drug delivery or othercontrolled-release system, using a biodegradable polymeric carrier isone effective means to deliver the therapeutic agent locally and in acontrolled fashion, see Langer et al., “Chemical and Physical Structuresof Polymers as Carriers for Controlled Release of Bioactive Agents”, J.Macro. Science, Rev. Macro. Chem. Phys., C23(1), 61-126 (1983). In thisway, less total drug is required, and toxic side effects can beminimized.

[0007] Polymers have been used for some time as carriers of therapeuticagents to effect a localized and sustained release. See Leong et al.,“Polymeric Controlled Drug Delivery”, Advanced Drug Delivery Rev.,1:199-233 (1987); Langer, “New Methods of Drug Delivery”, Science,249:1527-33 (1990) and Chien et al., Novel Drug Delivery Systems (1982).Such delivery systems offer the potential of enhanced therapeuticefficacy and reduced overall toxicity. Examples of classes of syntheticpolymers that have been studied as possible solid biodegradablematerials include polyesters (Pitt et al., “Biodegradable Drug DeliverySystems Based on Aliphatic Polyesters: Applications to Contraceptivesand Narcotic Antagonists”, Controlled Release of Bioactive Materials,19-44 (Richard Baker ed., 1980); poly(amino acids) and pseudo-poly(aminoacids) (Pulapura et al. “Trends in the Development of BioresorbablePolymers for Medical Applications”, J. Biomaterials Appl., 6:1, 216-50(1992); polyurethanes (Bruin et al., “Biodegradable LysineDiisocyanate-based Poly(Glycolide-co-ε Caprolactone)-Urethane Network inArtificial Skin”, Biomaterials, 11:4, 291-95 (1990); polyorthoesters(Heller et al., “Release of Norethindrone from Poly(Ortho Esters)”,Polymer Engineering Sci., 21:11, 727-31 (1981); and polyanhydrides(Leong et al., “Polyanhydrides for Controlled Release of BioactiveAgents”, Biomaterials 7:5, 364-71 (1986).

[0008] Polymers having phosphate linkages, called poly(phosphates),poly(phosphonates) and poly(phosphites), are known. See Penczek et al.,Handbook of Polymer Synthesis, Chapter 17: “Phosphorus-ContainingPolymers”, (Hans R. Kricheldorf ed., 1992). The respective structures ofthese three classes of compounds, each having a different side chainconnected to the phosphorus atom, are as follows:

[0009] The versatility of these polymers comes from the versatility ofthe phosphorus atom, which is known for a multiplicity of reactions. Itsbonding can involve the 3p orbitals or various 3s-3p hybrids; spdhybrids are also possible because of the accessible d orbitals. Thus,the physico-chemical properties of the poly(phosphoesters) can bereadily changed by varying either the R or R′ group. Thebiodegradability of the polymer is due primarily to the physiologicallylabile phosphoester bond in the backbone of the polymer. By manipulatingthe backbone or the side chain, a wide range of biodegradation rates areattainable.

[0010] An additional feature of poly(phosphoesters) is the availabilityof functional side groups. Because phosphorus can be pentavalent, drugmolecules or other biologically active substances can be chemicallylinked to the polymer. For example, drugs with —O-carboxy groups may becoupled to the phosphorus via a phosphoester bond, which ishydrolyzable. See, Leong, U.S. Pat. Nos. 5,194,581 and 5,256,765. TheP—O—C group in the backbone also lowers the glass transition temperatureof the polymer and, importantly, confers solubility in common organicsolvents, which is desirable for easy characterization and processing.

[0011] Copending U.S. application Ser. No. 09/053,648 and WO 98/44021disclose biodegradable terephthalate polyester-poly(phosphate)compositions; U.S. application Ser. No. 09/053,649 and WO 98/44020disclose biodegradable compositions containing polymers chain-extendedby phosphoesters; and U.S. application Ser. No. 09/070,204 andInternational Application No. PCT/US98/09185 disclose biodegradablecompositions comprising poly(cycloaliphatic phosphoester) compounds.However, none of these disclosures suggests the specific use ofbiodegradable poly(phosphoester) compositions for treating ovariancancer specifically.

[0012] Thus, there remains a need for new methods and materials for thedifficult problem of successfully treating ovarian cancer with a minimumof discomfort, toxicities and prolonged, periodic re-dosing.

SUMMARY OF THE INVENTION

[0013] It has now been discovered that biodegradable polymercompositions comprising:

[0014] (a) at least one antineoplastic agent and

[0015] (b) a biodegradable polymer comprising the recurring monomericunits shown in formula I:

[0016] wherein X is —O— or —NR⁴—, where R⁴ is H or alkyl;

[0017] Y is —O—, —S— or —NR⁴—;

[0018] each of R¹ and R² is a divalent organic moiety;

[0019] L is a divalent, branched or straight chain aliphatic grouphaving 1-20 carbon atom, a cycloaliphatic group, or a group having theformula:

[0020] R³ is selected from the group consisting of H, alkyl, alkoxy,aryl, aryloxy, heterocyclic or heterocycloxy; and

[0021] n is about 5-5,000;

[0022] are suitable for intraperitoneal administration to treat amammalian subject having ovarian cancer. These polymer compositionsprovide extended release of the antineoplastic agent within theperitoneum of the subject. Moreover, the polymer composition of theinvention increases the median survival rate from the cancer by at leastabout 10%, as compared with the median survival rate obtained byadministration of a composition comprising the same dosage of theantineoplastic agent without the biodegradable polymer of the invention.

[0023] The invention also comprises a solid article suitable forinsertion into the peritoneum to treat a mammalian subject havingovarian cancer, the article comprising a biodegradable polymercomposition comprising:

[0024] (a) at least one antineoplastic agent and

[0025] (b) a biodegradable polymer comprising the recurring monomericunits shown above in formula I.

[0026] In yet another embodiment of the invention, a method is providedfor treating a mammalian subject having ovarian cancer by the extendedrelease of an antineoplastic agent, the method comprising the steps of:

[0027] (a) combining the antineoplastic agent with a biodegradablepolymer having the recurring monomeric units shown above in formula I toform a composition; and

[0028] (b) inserting the composition in vivo into the peritoneum of thesubject, such that the inserted composition is in at least partial iscontact with an ovarian cancer tumor,

[0029] wherein the median survival rate from the cancer is increased byat least about 10%, as compared with the median survival rate obtainedby administration of a composition comprising the same dosage of theantineoplastic agent without the biodegradable polymer.

[0030] The compositions of the invention can be used to deliver a widevariety of antineoplastic agents, for example, from hydrophobic drugs,such as paclitaxel, to large water-soluble macromolecules, such asproteins, over an extended period of time without necessitatingsignificant volumes of a delivery fluid. The methods of the inventioncan thus be used to significantly increase the time period over which aneffective dose of the antineoplastic agent is released and increases thesurvival time of subjects treated by the method to an unexpected degree.Further, the serious disease of ovarian cancer can be therapeuticallymanaged with a minimum of side effects and without the unpleasantnessand discomfort of a periodic series of parenteral treatments introducingsignificant amounts of fluid into the peritoneum.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031]FIG. 1A shows the ¹H-NMR spectrum, and FIG. 1B shows the ³¹P-NMRspectrum for P(BHET-EOP/TC, 80/20).

[0032]FIG. 2 shows the FT-IR spectrum for P(BHET-EOP/TC, 80/20).

[0033]FIG. 3A shows the molecular weights and elemental analyses forP(BHET-EOP/TC, 80/20) and P(BHET-HOP/TC, 90/10), and FIG. 3B shows theGPC chromatogram for P(BHET-EOP/TC, 80/20).

[0034]FIG. 4A shows the DSC curve of P(BHET-EOP/TC, 80/20), and FIG. 4Bshows the DSC curve of P(BHET-EOP/TC, 50/50).

[0035]FIGS. 5A and 5B show the in vitro degradation data forP(BHET-EOP/TC, 80/20) and P(BHET-EOP/TC, 85/15).

[0036]FIG. 6 shows the change in molecular weight of P(BHDPT-EOP) andP(BHDPT-EOP/TC) poly(phosphoesters) during in vitro degradation.

[0037]FIGS. 7A and 7B show the in vivo degradation of P(BHET-EOP/TC) interms of weight or mass loss; FIG. 7C shows the controlled delivery ofhydrophobic small molecules, such as paclitaxel, from a p(BHET-EOP/TC,80/20) film.

[0038]FIG. 8 shows an electron microscopic photograph of P(BHET-EOP/TC,80/20) microspheres containing FITC-BSA.

[0039]FIG. 9A shows the effect of loading level on the release kineticsof FITC-BSA from microspheres, and 9B shows the controlled delivery ofhydrophobic small molecules, such as paclitaxel from a CHDM polymer.

[0040]FIG. 10 shows the release of lidocaine from copolymerP(BHDPT-EOP/TC) microspheres.

[0041]FIG. 11 shows the cytotoxicity of P(BHET-EOP/TC, 80/20)microspheres.

[0042]FIG. 12 shows a toxicity assay plot of relative cell growth (%)vs. concentration of degraded polymer in a tissue-culture well (mg/ml)for four separate polymers.

[0043]FIG. 13 shows the cytotoxicity of P(BHET-EOP/TC, 80/20)microspheres.

[0044]FIG. 14 shows the ¹H-NMR spectrum of a polymer of the invention,P(LAEG-EOP).

[0045]FIG. 15 shows the ³¹P-NMR spectrum of a polymer of the invention,P(LAEG-EOP).

[0046]FIGS. 16A and 16B show differential scanning calorimetry data fortwo polymers of the invention.

[0047]FIG. 17 shows the results of a GPC analysis of a polymer of theinvention in graphic form.

[0048]FIG. 18 shows the change in Mw of two polymers of the inventionafter being exposed to air at room temperature for one month.

[0049]FIG. 19 shows shelf stability data for a polymer of the inventionat room temperature.

[0050]FIGS. 20A and 20B show the weight loss (21A) and the change in Mw(21B) for discs fabricated from two polymers of the invention over aperiod of eight days in PBS at 37° C.

[0051]FIGS. 21A and 21B show the weight loss (22A) and the change in Mw(22B) for discs fabricated from two polymers of the invention, in vitro.

[0052]FIG. 22 shows biocompatibility data for polymers of the invention.

[0053]FIG. 23 shows cytotoxicity data for microspheres of a polymer ofthe invention, P(LAEG-EOP).

[0054]FIG. 24A shows the effect of fabrication method upon the releaserate of microspheres of a polymer of the invention, and 24B shows therate of release of lidocaine from microspheres of a polymer of theinvention.

[0055] FIGS. 25(A) through 25(E) all show degradation and release dataof p(DAPG-EOP) polymers in vitro.

[0056]FIG. 26 shows the structure of P(trans-CHDM-HOP) as determined by³¹P-NMR and ¹H-NMR.

[0057]FIG. 27 shows the chromatogram and molecular weight distributionfor P(cis-/trans-CHDM-HOP).

[0058]FIG. 28A graphically represents the active energy as a function offrequency of P(trans-CHDM-HOP), and FIG. 28B shows the correspondingviscosity.

[0059]FIG. 29A shows HEK293 cells grown on a P(CHDM-HOP) surface after72 hours of incubation, and FIG. 29B shows HEK293 cells grown on a TCPSsurface after 72 hours' incubation.

[0060]FIG. 30 graphically represents the effect of the side chainstructure on the in vitro degradation rate of three poly(phosphoesters)of the invention in phosphate buffer solution.

[0061]FIG. 31 shows the release curves of the bio-macromolecule FITC-BSAfrom the polymer P(CHDM-HOP) at 33% loading.

[0062]FIG. 32 graphically represents the in vitro release kinetics ofFITC-BSA as a function of a loading levels of 30%, 10% and 1%.

[0063]FIG. 33 graphically represents the in vitro effect of side chainstructure on the protein release kinetics of FITC-BSA with a 10% loadinglevel.

[0064]FIG. 34 shows the release of low molecular weight drugs(doxorubicin, cisplatin, and 5-fluorouracil) from P(CHDM-HOP).

[0065]FIG. 35 shows the calibration curves for the release of IL-2 froma P(CHDM-HOP) matrix in tissue culture medium.

[0066]FIG. 36 shows the distribution of tumor sizes in mice four weeksafter tumor implantation in an in vivo melanoma tumor model.

[0067]FIG. 37 shows the distribution of tumor sizes in mice six weeksafter tumor implantation in an in vivo melanoma tumor model.

[0068]FIG. 38 shows the percentage of survival as a function of time forfour different treatment groups in an in vivo melanoma tumor model.

[0069]FIG. 39 shows the release curves of two polymer compositions ofthe invention, one comprising the chemotherapeutic agent paclitaxel inthe polymer P(CHDM-EOP) and the other comprising paclitaxel in thepolymer P(CHDM-HOP).

[0070]FIG. 40 shows the efficacy of paclitaxel in a solvent andpaclitaxel in a p(DAPG-EOP) polymer in an ovarian cancer animal model(OVCAR3).

[0071]FIG. 41 shows the efficacy of p(DAPG-EOP) containing paclitaxel inan OVCAR3 ovarian cancer animal model.

[0072]FIG. 42 shows the efficacy of p(DAPG-EOP) containing paclitaxel inan OVCAR3 ovarian cancer animal model.

[0073]FIG. 43 shows further efficacy data for p(DAPG-EOP) containingpaclitaxel in an OVCAR3 ovarian cancer animal model.

[0074]FIG. 44 shows still further efficacy data for p(DAPG-EOP)containing paclitaxel in an OVCAR3 ovarian cancer animal model.

DETAILED DESCRIPTION OF THE INVENTION

[0075] Polymeric Compositions of the Invention

[0076] As used herein, the expression “a mammalian subject” refers toany mammalian subject, such as mice, rats, guinea pigs, cats, dogs,human beings, cows, horses, sheep, or other livestock. The expression “amammalian subject having ovarian cancer” includes, but is not limitedto, subjects suffering from current symptoms of this disease; subjectswho are recovering from other modes of treatment for the disease, suchas surgery, chemotherapy, or other treatment; and subjects simplybelieved to be at greater than average risk for ovarian cancer, such asthose who have at least partially recovered from the disease in the pastor those subjects having a significant number of female relativesdiagnosed as having or having had the disease.

[0077] As used herein, the term “treating” includes:

[0078] (i) preventing a disease, disorder or condition from occurring inan animal which may be predisposed to the disease, disorder and/orcondition but has not yet been diagnosed as having it;

[0079] (ii) inhibiting the disease, disorder or condition, i.e.,arresting its development; and

[0080] (iii) relieving the disease, disorder or condition, i.e., causingregression of the disease, disorder and/or condition.

[0081] The term “aliphatic” refers to a linear, branched or cyclicalkane, alkene, or alkyne. Preferred linear or branched aliphatic groupsin the poly(cycloaliphatic phosphoester) composition of the inventionhave from about 1 to 20 carbon atoms. Preferred cycloaliphatic groupsmay have one or more sites of unsaturation, i.e., double or triplebonds, but are not aromatic in nature.

[0082] As used herein, the term “aryl” refers to an unsaturated cycliccarbon compound with 4n+2 π electrons. As used herein, the term“heterocyclic” refers to a saturated or unsaturated ring compound havingone or more atoms other than carbon in the ring, for example, nitrogen,oxygen or sulfur. “Heteroaryl” refers to a heterocyclic compound with4n+2 electrons.

[0083] As used herein, the term “non-interfering substituent” means asubstituent that does react with the monomers; does not catalyze,terminate or otherwise interfere with the polymerization reaction; anddoes not react with the resulting polymer chain through intra- orinter-molecular reactions.

[0084] The biodegradable and injectable polymer composition of theinvention comprises a polymer having the recurring monomeric units shownin formula I:

[0085] wherein X is —O— or —NR⁴—, where R⁴ is H or alkyl, such asmethyl, ethyl, 1,2-dimethylethyl, n-propyl, isopropyl, 2-methylpropyl,2,2-dimethylpropyl or tert-butyl, n-pentyl, tert-pentyl, n-hexyl,n-heptyl and the like.

[0086] The group Y in formula I is —O—, —S— or —NR⁴—, where R⁴ is asdefined above.

[0087] Each of R¹ and R² can be any divalent organic moiety, which maybe either unsubstituted or substituted with one or more non-interferingsubstituents, so long as the moiety and its substituents do notinterfere undesirably with the polymerization, copolymerization, orbiodegradation reactions of the polymer. Specifically, each of R¹ and R²can be a branched or straight chain aliphatic group, preferably havingabout 1-20 carbon atoms. For example, R¹ and R² can be alkylene, such asmethylene, ethylene, 1-methylethylene, 1,2-dimethylethylene,n-propylene, isopropylene, 2-methylpropylene, 2,2′-dimethylpropylene ortert-butylene, n-pentylene, tert-pentylene, n-hexylene, n-heptylene,n-octylene, n-nonylene, n-decylene, n-undecylene, n-dodecylene, and thelike.

[0088] R¹ and R² can also be alkenylene, such as ethenylene,propenylene, 2-vinylpropenylene, n-butenylene, 3-ethenylbutylene,n-pentenylene, 4-(3-propenyl)hexylene, n-octenylene,1-(4-butenyl)-3-methyldecylene, dodecenylene, 2-(3-propenyl)dodecylene,hexadecenylene, and the like. R¹ and R² can also be alkynylene, such asethynylene, propynylene, 3-(2-ethynyl)pentylene, n-hexynylene,octadecenynylene, 2-(2-propynyl)decylene, and the like.

[0089] R¹ and R² can also be an aliphatic group, such as an alkylene,alkenylene or alkynylene group, substituted with a non-interferingsubstituent, for example, a hydroxy, halogen or nitrogen group. Examplesof such groups include, but are not limited to, 2-chloro-n-decylene,1-hydroxy-3-ethenylbutylene, 2-propyl-6-nitro-10-dodecynylene and thelike.

[0090] Further, R¹ and R² can be a cycloaliphatic group, such ascyclopentylene, 2-methylcyclopentylene, cyclohexylene, cyclohexenyleneand the like. Each of R¹ and R² can also be a divalent aromatic group,such as phenylene, benzylene, naphthalene, phenanthrenylene, and thelike, or a divalent aromatic group substituted with a non-interferingsubstituent. Further each of R¹ and R² can be a divalent heterocyclicgroup, such as pyrrolylene, furanylene, thiophenylene,alkylene-pyrrolylene-alkylene, pyridylene, pyridinylene, pyrimidinyleneand the like, or may be any of these substituted with a non-interferingsubstituent.

[0091] Preferably, R¹ and R² have from about 1-20 carbon atoms and arean alkylene group, a cycloaliphatic group, a phenylene group, or adivalent group having the formula:

[0092] wherein Z is oxygen, nitrogen, or sulfur, and m is 1 to 3. Morepreferably, each of R¹ and R² is a branched or straight chain alkylenegroup having from 1 to 7 carbon atoms. Most preferably, each of R¹ andR² is a methylene, ethylene group, n-propylene, 2-methylpropylene, or a2,2′-dimethylpropylene group.

[0093] In one embodiment of the invention, either R¹, R² or both R¹ andR², can be an antineoplastic agent in a form capable of being releasedin a physiological environment. When the antineoplastic agent part ofthe poly(phosphoester) backbone in this way, it is released as thepolymeric matrix formed by the composition of the invention degrades.

[0094] L in the polymer composition of the invention can be anydivalent, branched or straight chain aliphatic group having 1-20 carbonatom, a cycloaliphatic group, or a group having the formula:

[0095] When L is a branched or straight chain alkylene group, it ispreferably an alkylene group having from 1 to 7 carbon atoms, such as2-methylmethylene or ethylene. When L is a cycloaliphatic group, it maybe any divalent cycloaliphatic group so long as it does not interferewith the polymerization or biodegradation reactions of the polymer ofthe composition. Specific examples of useful unsubstituted andsubstituted cycloaliphatic L groups, include cycloalkylene groups suchas cyclopentylene, 2-methylcyclopentylene, cyclohexylene,2-chlorocyclohexylene, and the like; cycloalkenylene groups, such ascyclohexenylene; and cycloalkylene groups having fused or bridgedadditional ring structures on one or more sides, such as tetralinylene,decalinylene, and norpinanylene; or the like.

[0096] R³ in the polymer composition of the invention is selected fromthe group consisting of H, alkyl, alkoxy, aryl, aryloxy, heterocyclicand heterocycloxy residues.

[0097] When R³ is alkyl or alkoxy, it preferably contains about 1 toabout 20 carbon atoms, even more preferably about 1 to about 15 carbonatoms and, most preferably about 1-7 carbon atoms. Examples of suchgroups S include methyl, methoxy, ethyl, ethoxy, n-propyl, isopropoxy,n-butoxy, t-butyl, —C₈H₁₇; alkyl substituted with a non-interferingsubstituent, such as halogen, alkoxy or nitro; alkyl conjugated to abiologically active substance to form a pendant drug delivery system;and the like.

[0098] When R³ is aryl or the corresponding aryloxy group, it typicallycontains from about 5 to about 14 carbon atoms, preferably about 5 to 12carbon atoms and, optionally, can contain one or more rings that arefused to each other. Examples of particularly suitable aromatic groupsinclude phenyl, phenoxy, naphthyl, anthracenyl, phenanthrenyl and thelike.

[0099] When R³ is heterocyclic or heterocycloxy, it typically containsfrom about 5 to 14 ring atoms, preferably from about 5 to 12 ring atoms,and one or more heteroatoms. Examples of suitable heterocyclic groupsinclude furan, thiophene, pyrrole, isopyrrole, 3-isopyrrole, pyrazole,2-isoimidazole, 1,2,3-triazole, 1,2,4-triazole, oxazole, thiazole,isothiazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole,1,3,4-oxadiazole, 1,2,3,4-oxatriazole, 1,2,3,5-oxatriazole,1,2,3-dioxazole, 1,2,4-dioxazole, 1,3,2-dioxazole, 1,3,4-dioxazole,1,2,5-oxatriazole, 1,3-oxathiole, 1,2-pyran, 1,4-pyran, 1,2-pyrone,1,4-pyrone, 1,2-dioxin, 1,3-dioxin, pyridine, N-alkyl pyridinium,pyridazine, pyrimidine, pyrazine, 1,3,5-triazine, 1,2,4-triazine,1,2,3-triazine, 1,2,4-oxazine, 1,3,2-oxazine, 1,3,5-oxazine,1,4-oxazine, o-isoxazine, p-isoxazine, 1,2,5-oxathiazine,1,2,6-oxathiazine, 1,4,2-oxadiazine, 1,3,5,2-oxadiazine, azepine,oxepin, thiepin, 1,2,4-diazepine, indene, isoindene, benzofuran,isobenzofuran, thionaphthene, isothionaphthene, indole, indolenine,2-isobenzazole, 1,4-pyrindine, pyrando[3,4-b]-pyrrole, isoindazole,indoxazine, benzoxazole, anthranil, 1,2-benzopyran, 1,2-benzopyrone,1,4-benzopyrone, 2,1-benzopyrone, 2,3-benzopyrone, quinoline,isoquinoline, 12,-benzodiazine, 1,3-benzodiazine, naphthpyridine,pyrido[3,4-b]-pyridine, pyrido[3,2-b]-pyridine, pyrido[4,3-b]pyridine,1,3,2-benzoxazine, 1,4,2-benzoxazine, 2,3,1-benzoxazine,3,1,4-benzoxazine, 1,2-benzisoxazine, 1,4-benzisoxazine, carbazole,xanthrene, acridine, purine, and the like. Preferably, when R³ isheterocyclic or heterocycloxy, it is selected from the group consistingof furan, pyridine, N-alkylpyridine, 1,2,3- and 1,2,4-triazoles, indene,anthracene and purine rings.

[0100] In a particularly preferred embodiment, R³ is an alkyl group, analkoxy group, a phenyl group, a phenoxy group, or a heterocycloxy groupand, even more preferably, an alkoxy group having from 1 to 10 carbonatoms. Most preferably, R³ is an ethoxy or hexyloxy group.

[0101] Alternatively, the side chain R³ can be the antineoplastic agentor some other biologically active substance pendently attached to thepolymer backbone, for example by ionic or covalent bonding. In thispendant system, the antineoplastic agent or other biologically activesubstance is released as the bond connecting R³ with the phosphorousatom is cleaved under physiological conditions.

[0102] The number “n” can vary greatly depending on the biodegradabilityand the release characteristics desired in the polymer, but typicallyvaries between about 5 and 1,000. Preferably, n is from about 5 to about500 and, most preferably, is from about 5 to about 200.

[0103] When used in accordance with the method of the invention, thepolymer composition provides extended release of the antineoplasticagent into the peritoneum of a subject having ovarian cancer, preferablyfor a period greater than one week, more preferably for a period greaterthan two weeks. Even more preferably, this time extends for a periodgreater than about three weeks and, most preferably, is for a periodgreater than four weeks, for example, from four weeks to a year.

[0104] Further, use of the composition in accordance with the method ofthe invention increases the median survival rate from the cancer by atleast about 10%-, as compared with the median survival rate obtained byadministration of a composition comprising the same dosage ofantineoplastic agent without the biodegradable polymer of the invention.Preferably, the median survival rate is increased by at least about 20%,more preferably by at least 30% and, most preferably, by a factor of atleast about 40%.

[0105] The polymer used in the composition of the invention ispreferably selected from the group consisting of:

[0106] wherein R¹, R², R³ and n are as defined above.

[0107] In polymers of formula II, R⁵ is selected from the same groups asfor R¹ and R², and L is preferably a group having the formula:

[0108] The molar ratio of x:y in formula II can vary greatly dependingon the desired solubility of the polymer, the desired glass transitiontemperature (Tg), the desired stability of the polymer, the desiredstiffness of the final polymers, and the biodegradability and therelease characteristics desired in the polymer. However, the molar ratioof x:y typically varies between about 20:0 and 1:20. When y is 0, thepolymer formed is a homopolymer. Preferably, however, the ratio x:y isfrom about 1:15 to about 15:1, more preferably, from about 10:1 to Sabout 1:1.

[0109] The most common way of controlling the molar ratio of x:y is tovary the feed ratio of the “x” portion to the “y” portion whensynthesizing the polymer. Feed ratios can easily vary from 99: to 1:99,for example, 95:5, 90:10, 85:15, 80:20, 75:25, 70:30, 65:35, 60:40,55:45, 50:50, 45:55, 20:80, 15:85, and the like. Preferably, the monomerfeed ratio varies from about 90:10 to about 50:50, even more preferablyfrom about 80:20 to about 50:50 and, most preferably, from about 80:20to about 50:50.

[0110] Preferably, when the biodegradable polymer has formula II, R³ isalkoxy, aryloxy or heterocycloxy; x is about 0.1 to 30, more preferablyabout 0.2 to 20, most preferably ≧1 (for example, about 2-20); and y is2.

[0111] In preferred polymers of formula III and IV:

[0112] M¹ and M² are each independently (1) a branched or straight chainaliphatic group having from about 1-20 carbon atoms, even morepreferably from about 1-7 carbon atoms; or (2) a branched or straightchain, oxy-, carboxy- or amino-aliphatic group having from about 1-20carbon atoms, such as ethoxylene, 2-methylethoxylene, propoxylene,butoxylene, pentoxylene, dodecyloxylene, hexadecyloxylene, and the like;

[0113] each of x and y is about 1 to 1,000;

[0114] the molar ratio of x:y can vary greatly depending on thebiodegradability and the release characteristics desired in the polymerbut, typically, is about 1;

[0115] the molar ratio n:(x or y) can vary greatly depending on thebiodegradability and the release characteristics desired in the polymer,but typically varies between about 200:1 and 1:200, preferably 100:1 and1:100, more preferably from about 50:1 to about 1:50; and

[0116] the molar ratio q:r can also vary greatly depending on thebiodegradability and the release characteristics desired in the polymer,but typically varies between about 1:200 and 200:1, preferably betweenabout 1:150 to about 150:1 and, most preferably, between about 1:99 and99:1.

[0117] In formula III, each of M¹ and L preferably h from 1 to 7 carbonatoms. More preferably, M¹ is an ethylene group or a methyl-substitutedmethylene group, and L is an ethylene group.

[0118] In formula IV, each of M¹ and M² is preferably a branched orstraight chain alkylene or alkoxylene group, more preferably having from1-20 carbon atoms. Even more preferably, at least one of M¹ and M² is analkylene or alkoxylene group having a formula selected from the groupconsisting of —(CH₂)_(a)—, —(CH₂)_(a)—O—, and —(CH₂)_(a)—O—(CH₂)_(b)—,wherein each of a and b is 1-7.

[0119] When either M¹ and M² is a branched or straight chain,oxy-aliphatic group having from 1-20 carbon atoms it can also be, forexample, a dioxyalkylene group such as such as dioxymethylene,dioxyethylene, 1,3-dioxypropylene, 2-methoxy-1,3-dioxypropylene,1,3-dioxy-2-methylpropylene, dioxy-n-pentylene, dioxy-n-octadecylene,methoxylene-methoxylene, ethoxylene-methoxylene, ethoxylene-ethoxylene,ethoxylene-1-propoxylene, butoxylene-n-propoxylene,pentadecyloxylene-methoxylene, and the like. When M¹ and M² is abranched or straight chain, dioxo-aliphatic group, preferably it has theformula —O—(CH₂)_(a)—O— or —O—(CH₂)_(a)—O—(CH₂)_(b)—, wherein each of aand b is from 1-7.

[0120] When either M¹ or M² is a branched or straight chain,carboxy-aliphatic group having from 1-20 carbon atoms, it can also be,for example, a divalent carboxylic acid ester such as the divalentradical corresponding to methyl formate, methyl acetate, ethyl acetate,n-propyl acetate, isopropyl acetate, n-butyl acetate, ethyl propionate,allyl propionate, t-butyl acrylate, n-butyl butyrate, vinylchloroacetate, 2-methoxycarbonyl cyclohexanone, 2-acetoxycyclohexanone,and the like. When M¹ or M² is a branched or straight chain,carboxy-aliphatic group, it preferably has the formula —CHR′—CO—O—CHR″—,wherein R′ and R″ are each independently H, alkyl, alkoxy, aryl,aryloxy, heterocyclic or heterocycloxy.

[0121] When either M¹ or M² is a branched or straight chain,amino-aliphatic group having from 1-20 carbon atoms, it can be adivalent amine such as —CH₂NH—, —(CH₂)₂N—, —CH₂(C₂H₅)N—, -n-C₄H₉—NH—,-t-C₄H₉—NH—, —CH₂(C₃H₆)N—, —C₂H₅(C₃H₆)N—, —CH₂(C₈H₁₇)N—, and the like.When M¹ or M² is a branched or straight chain, amino-aliphatic group, itpreferably has the formula —(CH₂)_(a)— NR′ where R′ is H or lower alkyl,and “a” is from 1 to 7.

[0122] Preferably, M¹ and/or M² is an alkylene group having the formula—O—(CH₂)_(a)— where a is 1 to 7 and, most preferably, is a divalentethylene group. In another particularly preferred embodiment, M¹ and M²are n-pentylene and the divalent radical corresponding to methyl acetaterespectively.

[0123] In a preferred embodiment, L in formulas III and IV is a branchedor straight chain aliphatic group having from 1-20 carbon atoms, morepreferably an alkylene group having from 1 to 7 carbon atoms, such asethylene or methyl-substituted methylene.

[0124] In another particularly preferred polymer of formula IV, M¹ andM² are each an alkylene or alkoxylene group; L is an alkylene group; Xis —O—; and R³ is an alkoxy group. Most preferably, the biodegradablepolymer used in the invention comprises the recurring monomeric unitsshown in formula VI:

[0125] wherein the molar ratio of x:y is about 1;

[0126] the molar ratio n:(x or y) is between about 200:1 and 1:200; and

[0127] n is about 5-5,000.

[0128] When the polymer used has formula V:

[0129] preferably, each of R¹ and R² is independently straight orbranched aliphatic, such as a branched or straight chain alkylene grouphaving from 1 to 7 carbon atoms, for example methylene or ethylene,either unsubstituted or substituted with one or more non-interferingsubstituents;

[0130] L is a divalent cycloaliphatic group, such as cyclohexylene,either unsubstituted or substituted with a non-interfering substituent;

[0131] R³ is selected from the group consisting of H, alkyl, alkoxy,aryl, aryloxy, heterocyclic or heterocycloxy (preferably alkoxy such asethoxy or hexyloxy); and

[0132] n is about 5-5,000, even more preferably 5 to 500.

[0133] The molecular weight of the polymer used in the composition ofthe invention can vary widely, depending on whether a rigid solid state(higher molecular weights) desirable, or whether a flowable or flexiblestate (lower molecular weights) is desired. Generally, however,weight-average molecular weights (Mw) typically vary from about 2,000 toabout 400,000 daltons, preferably from about 2,000 to about 200,000daltons and, even more preferably, from about 2,000 to 60,000 daltons.Most preferably, the Mw varies between about 10,0000 to 55,000.Number-average molecular weight (Mn) can also vary widely, but generallyfall in the range of about 1,000 to about 200,000 daltons, preferablyfrom about 1,000 to about 100,000 daltons and, even more preferably,from about 1,000 to about 50,000 daltons. Most preferably, Mn variesbetween about 8,000 and 45,000 daltons.

[0134] A preferred method to determine molecular weight is by gelpermeation chromatography (“GPC”), e.g., mixed bed columns, CH₂Cl₂solvent, light scattering detector, and off-line dn/dc.

[0135] The glass transition temperature (Tg) of the polymer used in theinvention can vary widely depending upon the degree of branching in R¹and R², the relative proportion of phosphorous-containing monomer usedto make the polymer, and the like. When the article of the invention isa rigid solid, the Tg is preferably within the range of from about −10°C. to about 80° C., even more preferably between about 0 and 50° C. and,most preferably between about 25° C. to about 35° C.

[0136] In other embodiments, the Tg is preferably low enough to keep thecomposition of the invention flowable at body temperature. Then, theglass transition temperature of the polymer used in the invention ispreferably about 0 to about 37° C., more preferably from about 0 toabout 25° C.

[0137] The biodegradable polymer used in the invention is preferablysufficiently pure to be biocompatible itself and remains biocompatibleupon biodegradation. By “biocompatible”, it is meant that thebiodegradation products or the polymer itself are non-toxic and resultin only minimal tissue irritation when injected or placed into intimatecontact with vasculated tissues. The requirement for biocompatibility ismore easily accomplished because the presence of an organic solvent isnot required in the polymer composition of the invention.

[0138] However, the polymer used in the invention is preferably solublein one or more common organic solvents for ease of synthesis,purification and handling. Common organic solvents include such solventsas ethanol, chloroform, dichloromethane (dimethylene chloride), acetone,ethyl acetate, DMAC, N-methylpyrrolidone, dimethylformamide, anddimethylsulfoxide. The polymer is preferably soluble in at least one ofthe above solvents.

[0139] The polymer of the invention can also comprise additionalbiocompatible monomeric units so long as they do not interfere with thebiodegradable characteristics and the desirable flow characteristics ofthe invention. Such additional monomeric units may offer even greaterflexibility in designing the precise release profile desired fortargeted drug delivery or the precise rate of biodegradability desiredfor other applications. When such additional monomeric units are used,however, they should be used in small enough amounts to insure theproduction of a biodegradable copolymer having the desired physicalcharacteristics, such as rigidity, viscosity, flowability, flexibilityor a particular morphology.

[0140] Examples of such additional biocompatible monomers include therecurring units found in other poly(phosphoesters), poly(lactides),poly(glycolides), poly(caprolactones), poly(anhydrides), poly(amides),poly(urethanes), poly(esteramides), poly(orthoesters), poly(dioxanones),poly(acetals), poly(ketals), poly(carbonates), poly(orthocarbonates),poly(phosphazenes), poly(hydroxybutyrates), poly(hydroxyvalerates),poly(alkylene oxalates), poly(alkylene succinates), poly(malic acids),poly(amino acids), poly(vinylpyrrolidone), poly(ethylene glycol),poly(hydroxycellulose), chitin, chitosan, and copolymers, terpolymers,or combinations or mixtures of the above materials.

[0141] When additional monomeric units are used, those which have alower degree of crystallization and are more hydrophobic are preferred.Especially preferred recurring units with the desired physicalcharacteristics are those derived from poly(lactides),poly(caprolactones), and copolymers of these with glycolide, in whichthere are more amorphous regions.

[0142] General Synthesis of Phosphoester Polymers

[0143] The most common general reaction in preparing poly-(phosphates)is a dehydrochlorination between a phosphorodichloridate and a diolaccording to the following equation:

[0144] Most poly(phosphonates) are also obtained by condensation betweenappropriately substituted dichlorides and diols.

[0145] Poly(phosphites) have been prepared from glycols in a two-stepcondensation reaction. A 20% molar excess of a dimethylphosphite is usedto react with the glycol, followed by the removal of themethoxyphosphonyl end groups in the oligomers by high temperature.

[0146] An advantage of melt polycondensation is that it avoids the useof solvents and large amounts of other additives, thus makingpurification more straightforward. It can also provide polymers ofreasonably high molecular weight. Somewhat rigorous conditions, however,are often required and can lead to chain acidolysis (or hydrolysis ifwater is present). Unwanted, thermally-induced side reactions, such ascrosslinking reactions, can also occur if the polymer backbone issusceptible to hydrogen atom abstraction or oxidation with subsequentmacroradical recombination.

[0147] To minimize these side reactions, the polymerization can also becarried out in solution. Solution polycondensation requires that boththe prepolymer and the phosphorus component be soluble in a commonsolvent. Typically, a chlorinated organic solvent is used, such aschloroform, dichloromethane, or dichloroethane.

[0148] A solution polymerization is preferably run in the presence ofequimolar amounts of the reactants and a stoichiometric amount of anacid acceptor, usually a tertiary amine such as pyridine ortriethylamine. Reaction times tend to be longer with solutionpolymerization than with melt polymerization. However, because overallmilder reaction conditions can be used, side reactions are minimized,and more sensitive functional groups can be incorporated into thepolymer. Moreover, attainment of high molecular weights is less likelywith solution polymerization.

[0149] Interfacial polycondensation can be used when high reaction ratesare desired. The mild conditions used minimize side reactions, and thereis no need for stoichiometric equivalence between the diol anddichloridate starting materials as in solution methods. However,hydrolysis of the acid chloride may occur in the alkaline aqueous phase.Sensitive dichloridates that have some solubility in water are generallysubject to hydrolysis rather than polymerization. Phase transfercatalysts, such as crown ethers or tertiary ammonium chloride, can beused to bring the ionized diol to the interface to facilitate thepolycondensation reaction. The yield and molecular weight of theresulting polymer after interfacial polycondensation are affected byreaction time, molar ratio of the monomers, volume ratio of theimmiscible solvents, the type of acid acceptor, and the type andconcentration of the phase transfer catalyst.

[0150] The purpose of the polymerization reaction is to form a polymercomprising (i) divalent organic recurring units and (ii) phosphoesterrecurring units. The result can be a homopolymer, a relativelyhomogeneous copolymer, or a block copolymer that has a somewhatheterogeneous microcrystalline structure. Any one of these threeembodiments is well-suited for use as a controlled release medium.

[0151] While the process may be in bulk, in solution, by interfacialpolycondensation, or any other convenient method of polymerization,preferably, the process takes place under solution conditions.Particularly useful solvents include methylene chloride, chloroform,tetrahydrofuran, dimethyl formamide, dimethyl sulfoxide, toluene, or anyof a wide variety of other inert organic solvents.

[0152] Particularly when solution polymerization reaction is used, anacid acceptor is advantageously present during the polymerizationreaction. A particularly suitable class of acid acceptor comprisestertiary amines, such as pyridine, trimethylamine, triethylamine,substituted anilines and substituted aminopyridines. The most preferredacid acceptor is the substituted aminopyridine 4-dimethylaminopyridine(“DMAP”).

[0153] In a particularly preferred embodiment of the invention, forexample, the biodegradable polymer of formula III or IV is made by aprocess comprising the steps of:

[0154] (a) reacting at least one heterocyclic ring compound havingformula VII, VIII or IX:

[0155] wherein M¹, M² and X are as defined above, with an initiatorhaving the formula:

H—Y-L-Y—H,

[0156] wherein Y and L are as defined as above, to form a prepolymer offormula X or XI, shown below:

[0157] wherein X, M¹, M², Y, L, R, x, y, q and r are as defined above;and

[0158] (b) further reacting the prepolymer with a phosphorodihalidate offormula XII:

[0159] where “halo” is Br, Cl or I; and R³ is as defined above, to forma polymer of formula III or IV.

[0160] The function of the first reaction step (a) is to use theinitiator to open the ring of the heterocyclic ring compound of formulaVII, VIII or IX. Examples of useful heterocyclic compounds of formulaVII, VIII or IX include caprolactones, caprolactams, amino acidanhydrides such as glycine anhydride, cycloalkylene carbonates,dioxanones, glycolids, lactides and the like.

[0161] When the compound of the invention has formula III, only oneheterocyclic ring compound of formula VII, which contains M¹, may beused to prepare the prepolymer in step (a). When the compound of theinvention has formula IV, then a combination of a heterocyclic compoundof formula VII, which contains M¹, and a heterocyclic compound offormula VIII, which contains M² may be used in step (a). Alternatively,when the compound of the invention has formula IV, a single heterocycliccompound of formula IX, which contains both M¹ and M² can be used instep (a).

[0162] Examples of suitable initiators include a wide variety ofcompounds having at least two active hydrogens (H—Y-L-Y—H) where L is alinking group and is defined above, and Y can be —O—, —S— or —NR⁴, whereR⁴ is as defined above. The linking group L is can be a straight chaingroup, e.g., alkylene, but it may also be substituted with one or moreadditional active-hydrogen-containing groups. For example, L may be astraight chain alkylene group substituted with one or more additionalalkyl groups, each bearing a activated hydrogen moiety, such as —OH,—SH, or NH₂. In this way, various branched polymers can be preparedusing the branched active hydrogen initiators to design the resultingpolymer such that it has the desired properties. However, when branchedpolymers are reacted with acid chlorides, cross-linked polymers willresult.

[0163] The reaction step (a) can take place at widely varyingtemperatures, depending upon the solvent used, the molecular weightdesired, the susceptibility of the reactants to form side reactions, andthe presence of a catalyst. Preferably, however, the reaction step (a)takes place at a temperature from about 0 to about +235° C. for meltconditions. Somewhat lower temperatures may be possible with the use ofeither a cationic or anionic catalyst.

[0164] While the reaction step (a) may be in bulk, in solution, byinterfacial polycondensation, or any other convenient method ofpolymerization, preferably, the reaction step (a) takes place under meltconditions.

[0165] Examples of particularly useful prepolymers of formula X include:

[0166] (i) OH-terminated prepolymer derived from polycaprolactoneH—[—O(CH₂)₅—CO—]_(x)—O—CH₂—CH₂—O—[—CO—(CH₂)₅—O—] _(y)—H;

[0167] (ii) NH-terminated prepolymer derived from polycaprolactam (Nylon6) H—[—NH—(CH₂)₅—CO—]_(x)—NH—CH₂—CH₂—NH—[—CO—(CH₂)₅—NH—]_(y)—H;

[0168] (iii) OH-terminated prepolymer derived from polylactideH—[—OCH(CH₃)—CO—]_(x)—O—CH₂—CH₂—O—[—CO—CH(CH₃)—O—]_(y)—H; and

[0169] (iv) OH-terminated prepolymer derived from polytrimethylenecarbonate H—[—O(CH₂)₃—O—CO—]_(x)—O—CH₂—CH₂—O—[—CO—O—(CH₂)₃—O—]_(y)—H

[0170] Examples of particularly useful prepolymers of formula XIinclude:

[0171] (i) OH-terminated copolymer derived from lactide and glycolide:

[0172] (ii) OH-terminated copolymer derived from lactide andcaprolactone:

[0173]  and

[0174] (iii) OH-terminated copolymer derived from glycolide andcaprolactone:

[0175] The purpose of the polymerization of step (b) is to form apolymer comprising (i) the prepolymer produced as a result of step (a)and (ii) interconnecting phosphorylated units. The result can be a blockcopolymer having a microcrystalline structure that is particularlywell-suited to use as a controlled release medium.

[0176] The polymerization step (b) of the invention usually takes placeat a slightly lower temperature than the temperature of step (a), butalso may vary widely, depending upon the type of polymerization reactionused, the presence of one or more catalysts, the molecular weightdesired, and the susceptibility of the reactants to undesirable sidereaction. When melt conditions are used, the temperature may vary fromabout 0-150° C. However, when the polymerization step (b) is carried outin a solution polymerization reaction, it typically takes place at atemperature between about −40 and 100° C.

[0177] Antineoplastic Agent

[0178] Generally speaking, the antineoplastic agent of the invention canvary widely depending upon the pharmacological strategy selected forinhibiting, destroying, or preventing the ovarian cancer. Theantineoplastic agent may be described as a single entity or acombination of entities. The compositions, articles and methods aredesigned to be used with antineoplastic agents having highwater-solubility, as well as those having low water-solubility, toproduce a delivery system that has controlled release rates.

[0179] The term antineoplastic agent includes, without limitation,alkylating agents, such as carboplatin and cisplatin; nitrogen mustardalkylating agents; nitrosourea alkylating agents, such as carmustine(BCNU); antimetabolites, such as methotrexate; purine analogantimetabolites; pyrimidine analog antimetabolites, such as fluorouracil(5-FU) and gemcitabine; hormonal antineoplastics, such as goserelin,leuprolide, and tamoxifen; natural antineoplastics, such as aldesleukin,interleukin-2, docetaxel, etoposide (VP-16), interferon alfa,paclitaxel, and tretinoin (ATRA); antibiotic natural antineoplastics,such as bleomycin, dactinomycin, daunorubicin, doxorubicin, andmitomycin; and vinca alkaloid natural antineoplastics, such asvinblastine and vincristine. Preferably, the antineoplastic agent isselected from the group consisting of paclitaxel, BCNU, carboplatin andcisplatin. Most preferably, the antineoplastic agent is paclitaxel.

[0180] Further, the following additional drugs may also be used incombination with the antineoplastic agent, even if not consideredantineoplastic agents themselves: dactinomycin; daunorubicin HCl;docetaxel; doxorubicin HCl; epoetin alfa; etoposide (VP-16); ganciclovirsodium; gentamicin sulfate; interferon alfa; leuprolide acetate;meperidine HCl; methadone HCl; ranitidine HCl; vinblastin sulfate; andzidovudine (AZT). For example, fluorouracil has recently been formulatedin conjunction with epinephrine and bovine collagen to form aparticularly effective combination.

[0181] Still further, the following listing of amino acids, peptides,polypeptides, proteins, polysaccharides, and other large molecules mayalso be used: interleukins 1 through 18, including mutants andanalogues; interferons or cytokines, such as interferons α, β, and γ;hormones, such as luteinizing hormone releasing hormone (LHRH) andanalogues and, gonadotropin releasing hormone (GnRH); growth factors,such as transforming growth factor-β (TGF-β), fibroblast growth factor(FGF), nerve growth factor (NGF), growth hormone releasing factor(GHRF), epidermal growth factor (EGF), fibroblast growth factorhomologous factor (FGFHF), hepatocyte growth factor (HGF), and insulingrowth factor (IGF); tumor necrosis factor-α & β (TNF-α & β); invasioninhibiting factor-2 (IIF-2); bone morphogenetic proteins 1-7 (BMP 1-7);somatostatin; thymosin-α-1; γ-globulin; superoxide dismutase (SOD);complement factors; anti-angiogenesis factors; antigenic materials; andpro-drugs.

[0182] In particularly preferred embodiment, the composition of theinvention may comprise other biologically active substances, preferablya therapeutic drug or pro-drug, for example, other chemotherapeuticagents, antibiotics, anti-virals, anti-fungals, anti-inflammatories, andanticoagulants, antigens useful for cancer vaccine applications orcorresponding pro-drugs.

[0183] Various forms of the antineoplastic agents and/or otherbiologically active agents may be used. These include, withoutlimitation, such forms as uncharged molecules, molecular complexes,salts, ethers, esters, amides, and the like, which are biologicallyactivated when implanted, injected or otherwise placed into the body.

[0184] In a particularly preferred embodiment, a biodegradable polymercomposition suitable for intraperitoneal administration to treat amammalian subject having ovarian cancer comprises:

[0185] (a) paclitaxel and

[0186] (b) a biodegradable polymer comprising the recurring monomericunits shown in formula VI:

[0187] wherein the molar ratio of x:y is about 1;

[0188] the molar ratio n:(x or y) is between about 200:1 and 1:200; and

[0189] n is about 5-5,000.

[0190] Biodegradation and Release Characteristics

[0191] Biodegradable polymers differ from non-biodegradable polymers inthat they can be degraded during in vivo therapy. This generallyinvolves breaking down the polymer into its monomeric subunits. Inprinciple, the ultimate hydrolytic breakdown products of the polymerused in the invention are a cycloaliphatic diol, an aliphatic alcoholand phosphate. All of these degradation products are potentiallynon-toxic. However, the intermediate oligomeric products of thehydrolysis may have different properties. Thus, the toxicology of abiodegradable polymer intended for insertion into the body, even onesynthesized from apparently innocuous monomeric structures, is typicallydetermined after one or more toxicity analyses.

[0192] There are many different ways of testing for toxicity and/orbiocompatibility known to those of ordinary skill in the art. A typicalin vitro toxicity assay, however, would be performed with live carcinomacells, such as GT3TKB tumor cells, in the following manner:

[0193] Two hundred microliters of various concentrations of the degradedpolymer products are placed in 96-well tissue culture plates seeded withhuman gastric carcinoma cells (GT3TKB) at 10⁴/well density. The degradedpolymer products are incubated with the GT3TKB cells for 48 hours. Theresults of the assay can be plotted as % relative growth vs.concentration of degraded polymer in the tissue-culture well.

[0194] Polymers can also be evaluated by well-known in vivobiocompatibility tests, such as by subcutaneous implantation orinjection in rats to confirm that the systems hydrolyze withoutsignificant levels of irritation or inflammation at the insertion site.

[0195] The polymer of formula I is usually characterized by abiodegradation rate that is controlled at least in part as a function ofhydrolysis of the phosphoester bond of the polymer. Other factors arealso important. For example, the lifetime of a biodegradable polymer invivo also depends upon its molecular weight, crystallinity,biostability, and the degree of crosslinking. In general, the greaterthe molecular weight, the higher the degree of crystallinity, and thegreater the biostability, the slower biodegradation will be. Inaddition, the rate of degradation of the polymer can be furthercontrolled by choosing a side chain of differing lengths. Accordingly,degradation times can very widely, preferably from less than a day toseveral months.

[0196] Accordingly, the structure of the side chain can influence therelease behavior of compositions comprising a biologically activesubstance. For example, it is expected that conversion of the phosphateside chain to a more lipophilic, more hydrophobic or bulky group wouldslow down the degradation process. Thus, release is usually faster frompolymer compositions with a small aliphatic group side chain than with abulky aromatic side chain.

[0197] The expression “extended release”, as used herein, includes,without limitation various forms of release, such as controlled release,timed release, sustained release, delayed release, long acing, andpulsatile delivery, immediate release that occurs with various rates.The ability to obtain extended release, controlled release, timedrelease, sustained release, delayed release, long acting, pulsatiledelivery or immediate release is performed using well-known proceduresand techniques available to the ordinarily skilled artisan. None ofthese specific techniques or procedures constitute an inventive aspectof this invention.

[0198] Polymer Compositions

[0199] The antineoplastic agents are used in amounts that aretherapeutically effective, which varies widely depending largely on theparticular antineoplastic agent being used. The amount of antineoplasticagent incorporated into the composition also depends upon the desiredrelease profile, the concentration of the agent required for abiological effect, and the length of time that the biologically activesubstance has to be released for treatment. Preferably, the biologicallyactive substance is blended with the polymer matrix of the invention atdifferent loading levels, preferably at room temperature and without theneed for an organic solvent.

[0200] There is no critical upper limit on the amount of antineoplasticagent incorporated except for that of an acceptable solution ordispersion viscosity to maintain the physical characteristics desiredfor the composition. The lower limit of the antineoplastic agentincorporated into the delivery system is dependent upon the activity ofthe drug and the length of time needed for treatment. Thus, the amountof the antineoplastic agent should not be so small that it fails toproduce the desired physiological effect, nor so large that theantineoplastic agent is released in an uncontrollable manner.

[0201] Typically, within these limits, amounts of the antineoplasticagent from about 11 up to about 65% can be incorporated into the presentdelivery systems. However, lesser amounts may be used to achieveefficacious levels of treatment for antineoplastic agent that areparticularly potent.

[0202] In addition, the polymer composition of the invention can alsocomprise blends of the polymer of the invention with other biocompatiblepolymers or copolymers, so long as the additional polymers or copolymersdo not interfere undesirably with the biodegradable or mechanicalcharacteristics of the composition. Blends of the polymer of theinvention with such other polymers may offer even greater flexibility indesigning the precise release profile desired for targeted drug deliveryor the precise rate of biodegradability desired. Examples of suchadditional biocompatible polymers include other poly(phosphoesters),poly(carbonates), poly(esters), poly(orthoesters), poly(amides),poly(urethanes), poly(imino-carbonates), and poly(anhydrides).

[0203] Pharmaceutically acceptable polymeric carriers may also comprisea wide range of additional materials. Without being limited thereto,such materials may include diluents, binders and adhesives, lubricants,disintegrants, colorants, bulking agents, flavorings, sweeteners, andmiscellaneous materials such as buffers and adsorbents, in order toprepare a particular medicated composition, with the condition that noneof these additional materials will interfere with the biocompatibility,biodegradability and physical state desired of the polymer compositionsof the invention.

[0204] For delivery of an antineoplastic agent or some otherbiologically active substance, the agent or substance is added to thepolymer composition. The agent or substance is either dissolved to forma homogeneous solution of reasonably constant concentration in thepolymer composition, or dispersed to form a suspension or dispersionwithin the polymer composition at a desired level of “loading” (grams ofbiologically active substance per grams of total composition includingthe biologically active substance, usually expressed as a percentage).

[0205] While it is possible that the biodegradable polymer or thebiologically active agent may be dissolved in a small quantity of asolvent that is non-toxic to more efficiently produce an amorphous,monolithic distribution or a fine dispersion of the biologically activeagent in the flexible or flowable composition, it is an advantage of theinvention that, in a preferred embodiment, no solvent is needed to forma flowable composition. Moreover, the use of solvents is preferablyavoided because, once a polymer composition containing solvent is placedtotally or partially within the body, the solvent dissipates or diffusesaway from the polymer and must be processed and eliminated by the body,placing an extra burden on the body's clearance ability at a time whenthe illness (and/or other treatments for the illness) may have alreadydeleteriously affected it.

[0206] However, when a solvent is used to facilitate mixing or tomaintain the flowability of the polymer composition of the invention, itshould be non-toxic, otherwise biocompatible, and should be used inminimal amounts. Solvents that are toxic clearly should not be used inany material to be placed even partially within a living body. Such asolvent also must not cause tissue irritation or necrosis at the site ofadministration.

[0207] Examples of suitable biocompatible solvents, when used, includeN-methyl-2-pyrrolidone, 2-pyrrolidone, ethanol, propylene glycol,acetone, methyl acetate, ethyl acetate, methyl ethyl ketone,dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, caprolactam,dimethyl-sulfoxide, oleic acid, or 1-dodecylazacycloheptan-2-one.Preferred solvents include N-methyl-2-pyrrolidone, 2-pyrrolidone,dimethyl sulfoxide, and acetone because of their solvating ability andtheir biocompatibility.

[0208] The polymer composition of the invention may be a flexible orflowable material. By “flowable” is meant the ability to assume, overtime, the shape of the space containing it at body temperature. Thisincludes, for example, liquid compositions that are capable of beingsprayed into a site; injected with a manually operated syringe fittedwith, for example, a 23-gauge needle; or delivered through a catheter.

[0209] Also included by the term “flowable”, however, are highlyviscous, “gel-like” materials at room temperature that may be deliveredto the desired site by pouring, squeezing from a tube, or being injectedwith any one of the commercially available power injection devices thatprovide injection pressures greater than would be exerted by manualmeans alone for highly viscous, but still flowable, materials. When thepolymer used is itself flowable, the polymer composition of theinvention, even when viscous, need not include a biocompatible solventto be flowable, although trace or residual amounts of biocompatiblesolvents may still be present. The degree of viscosity of the polymercan be adjusted by the molecular weight of the polymer, as well as bymixing the cis- and trans-isomers of the cyclohexane dimethanol in thebackbone of the polymer.

[0210] The polymer composition of the invention can be administered by avariety of routes. For example, if flowable, it can be injected to form,after injection, a temporary biomechanical barrier to coat orencapsulate internal organs or tissues. The polymer composition of theinvention can also be used to produce coatings for solid implantabledevices.

[0211] However, most importantly, the polymer composition of theinvention provides controllable and effective release of theantineoplastic agent over time, even in the case of largebio-macromolecules.

[0212] Implants and Delivery Systems

[0213] In its simplest form, a biodegradable polymer delivery systemconsists of a solution or dispersion of an antineoplastic agent in apolymer matrix having an unstable (biodegradable) bond incorporated intothe polymer backbone. In a particularly preferred embodiment, a solidarticle comprising the composition of the invention is inserted withinthe peritoneum by implantation, injection, laparoscopy or otherwisebeing placed within the peritoneum of the subject being treated, forexample, during or after the surgical removal of visibly canceroustissue.

[0214] The antineoplastic agent of the composition and the polymer mayform a homogeneous matrix, or the biologically active substance may beencapsulated in some way within the polymer. For example, thebiologically active substance may be first encapsulated in a microsphereand then combined with the polymer in such a way that at least a portionof the microsphere structure is maintained. Alternatively, thebiologically active substance may be sufficiently immiscible in thepolymer of the invention that it is dispersed as small droplets, ratherthan being dissolved, in the polymer.

[0215] As a structural medical device, the polymer compositions of theinventions provide a wide variety of physical forms having specificchemical, physical and mechanical properties suitable for insertion intothe peritoneum, in addition to being a composition that degrades in vivointo non-toxic residues.

[0216] Biodegradable drug delivery articles can be prepared in severalways. The polymer can be melt processed using conventional extrusion orinjection molding techniques, or these products can be prepared bydissolving in an appropriate solvent, followed by formation of thedevice, and subsequent removal of the solvent by evaporation orextraction, e.g., by spray drying. By these methods, the polymers may beformed into articles of almost any size or shape desired, for example,implantable solid discs or wafers or injectable rods, microspheres, orother microparticles. Typical medical articles also include such asimplants as laminates for degradable fabric or coatings to be placed onother implant devices.

[0217] The antineoplastic agent is typically released from the polymericmatrix at least as quickly as the matrix biodegrades in vivo. With someantineoplastic agents, the agent will be released only after the polymerhas been degraded to a point where a non-diffusing substance has beenexposed to bodily fluids. As the polymer begins to degrade, thebiologically active substance that was completely surrounded by thepolymer matrix begins to be liberated.

[0218] However, with this mechanism, a long peptide chain that isphysically entangled in a rigid solid implant structure may tend todegrade along with the matrix and break off from the remainder of thepeptide chain, thereby releasing incomplete fragments of molecules. Whenthe polymer compositions of the invention are designed to be flexible,however, the polymer will typically degrade after the peptide or proteinhas been released in part. In a particularly preferred mechanism, when apeptide chain is being released from the composition of the invention,the composition remains flexible and allows a large-molecule protein to,at least partially, diffuse through the polymeric matrix prior to itsown or the polymer's biodegradation.

[0219] The initial release rate of proteins from the compositions istherefore generally diffusion-controlled through channels in the matrixstructure, the rate of which is inversely proportional to the molecularweight of the protein. Once polymer degradation begins, however, theprotein remaining in the matrix may also be released by the forces oferosion.

[0220] The biodegradable amorphous matrices of the invention typicallycontain polymer chains that are associated with other chains. Theseassociations can be created by a simple entanglement of polymer chainswithin the matrix, as opposed to hydrogen bonding or Van der Vaalsinteractions or between crystalline is regions of the polymer orinteractions that are ionic in nature. Alternatively, the synthesis ofblock copolymers or the blending of two different polymers can be usedto create viscous, “putty-like” materials with a wide variation inphysical and mechanical properties.

[0221] In a particularly preferred embodiment, the composition of theinvention is sufficiently flowable to be injected into the body. It isparticularly important that the injected composition result in minimaltissue irritation after injection or otherwise being inserted into theperitoneal cavity.

[0222] In one embodiment, the polymer composition of the invention isused to form a soft, drug-delivery “depot” that can be administered as aliquid, for example, by injection, but which remains sufficientlyviscous to maintain the drug within the localized area around theinjection site. The degradation time of the depot so formed can bevaried from several days to a year or more, depending upon the polymerselected and its molecular weight. By using a polymer composition inflowable form, even the need to make an incision can be eliminated. Inany event, the flexible or flowable delivery “depot” will adjust to theshape of the space it occupies within the body with a minimum of traumato surrounding tissues.

[0223] When the polymer composition of the invention is flexible orflowable, it can be placed anywhere within the body, including a cavitysuch as the peritoneum, sprayed onto or poured into open wounds, or usedas a site delivery system during surgery. When flowable, the compositionof the invention can also be used to act as a temporary barrier inpreventing the direct adhesion of different types of tissue to eachother, for example, after abdominal surgery, due to its ability toencapsulate tissues, organs and prosthetic devices.

[0224] Once inserted, the polymer composition of the invention shouldremain in at least partial contact with a biological fluid, such asblood, internal organ secretions, mucous membranes, and the like. Theimplanted or injected composition will release the antineoplastic agentcontained within its matrix at a controlled rate until the substance isdepleted, following the general rules for diffusion or dissolution froma rigid, flexible or flowable biodegradable polymeric matrix.

[0225] The following examples are illustrative of preferred embodimentsof the invention and are not to be construed as limiting the inventionthereto. All polymer molecular weights are average molecular weights.All percentages are based on the percent by weight of the final deliverysystem or formulation being prepared, unless otherwise indicated, andall totals equal 100% by weight.

EXAMPLES Example 1 Synthesis of Copolymer P(BHET-EOP/TC, 80/20)

[0226]

[0227] Under an argon stream, 10 g of 1,4-bis(hydroxyethyl)terephthalate (BHET), 9.61 g of 4-dimethylaminopyridine (DMAP) and 70 mLof methylene chloride were placed in a 250 mL flask equipped with afunnel. The solution in the flask was cooled down to −40° C. withstirring, and a solution of 5.13 g of ethyl phosphorodichloridate (EOP)(distilled before use) in 20 mL of methylene chloride was added dropwisethrough the funnel. After addition was complete, the mixture was stirredat room temperature for four hours to form the homopolymer BHET-EOP.

[0228] A solution of 1.60 g of terephthaloyl chloride (TC) (obtainedfrom Aldrich Chemical Company and recrystallized with hexane before use)in 20 mL of methylene chloride was then added drop by drop. Thetemperature was brought up to about 45-50° C. gradually, and thereaction mixture was kept refluxing overnight to complete thecopolymerization of the homopolymer P(BHET-EOP) with the additionalmonomer TC to form the copolymer P(BHET-EOP/TC).

[0229] The solvent was then evaporated, and the residue was redissolvedin about 100-200 mL of chloroform. The chloroform solution was washedwith a saturated NaCl solution three times, dried over anhydrous Na₂SO₄,and quenched into ether. The resulting precipitate was redissolved inchloroform and quenched again into ether. The resulting tough, off-whitesolid precipitate was filtered off and dried under vacuum. Yield 82%.

[0230] The structure of P(BHET-EOP/TC, 80/20) was ascertained by ¹H-NMR,³¹P-NMR and FT-IR spectra, as shown in FIGS. 1 and 2. The structure wasalso confirmed by elemental analysis, which correlated closely withtheoretical ratios. The results of the elemental analysis are shown inFIG. 3.

[0231] The molecular weight of P(BHET-EOP/TC, 80/20) was first measuredby gel permeation chromatography (GPC) with polystyrene as thecalibration standard. The resulting graph established a weight averagemolecular weight (Mw) of about 6100 and a number average molecularweight (Mn) of about 2200, as shown in FIG. 4. Vapor pressure osmometry(UVPOII) for this copolymer gave an Mn value of about 7900. The resultsof these molecular weight studies are also shown in FIG. 3.

Example 2 Feed Ratio Variations of P(BHET-EOP/TC)

[0232] A series of other P(BHET-EOP/TC) copolymers of the invention wereprepared by following the procedure described above in Example 1 exceptthat the feed ratio of the EOP to TC used during the initialpolymerization step and copolymerization step respectively was varied.The results are shown below in Table 1. From the feed ratio of EOP/TC,the value of “x” from the formula shown below can be calculated. Forexample, in P(BHET-EOP/TC, 80/20) prepared above in Example 1, x is 8.TABLE 1 Variation of Feed Ratio of EOP to TC in P(BHET-EOP/TC)

Feed Ratio of EOP/TC* 100/0 95/5 90/10 85/15 80/20 50:50 “x” — 38 1811.4 8 2

Example 3 Synthesis and Isolation of the Homopolymer P(BHDPT-EOP)

[0233]

[0234] The BHDPT monomer prepared in Example 5 above and the acidacceptor 4-dimethylaminopyridine (DMAP) were dissolved in methylenechloride. The resulting solution was chilled to −70° C. using a dryice/acetone bath, and an equal molar amount of ethylphosphorodichloridate (EOP) was slowly added. The reaction mixture wasthen heated and refluxed overnight. The salt formed in thepolymerization was removed by filtration. The remaining polymer solution(filtrate) was washed with a saturated NaCl solution three times, andthe homopolymer was precipitated in diethyl ether.

Example 4 Synthesis of Copolymer P(BHDPT-EOP/TC)

[0235]

[0236] Copolymers of P(BHDPT-EOP) with TC were synthesized by thetwo-step solution copolymerization shown above. After the reactionbetween BHDPT and EOP had proceeded at room temperature for one hour,the reaction flask was cooled in a dry ice/acetone bath. An appropriateamount of TC (the number of moles of TC and EOP combined equaled thenumber of moles of BHDPT) was slowly added to the flask. The reactionmixture was then heated and refluxed overnight. The salt formed in thepolymerization was removed by filtration. The remaining copolymersolution (filtrate) was washed with a saturated NaCl solution threetimes, and the copolymer was precipitated out in diethyl ether.

Example 5 Synthesis of Poly(Phosphoester) P(BHDPT-HOP/TC)

[0237]

[0238] Copolymers of P(BHDPT-HOP) with TC were synthesized by a two-stepsolution polymerization. After the reaction between BHDPT and HOP hadproceeded at room temperature for one hour, the reaction flask wascooled in a dry ice/acetone bath. An appropriate amount of TC (thenumber of moles of TC and HOP combined equaled the number of moles ofBHDPT) was slowly added to the flask. The reaction mixture was thenheated and refluxed overnight. The salt formed during thecopolymerization was removed by filtration. The remaining copolymersolution (filtrate) was washed with a saturated NaCl solution threetimes, and the copolymer was precipitated out in diethyl ether.

Example 6 Other Diol Variations

[0239] Diol terephthalates that are structurally related to that of BHETand BHDPT were synthesized by reacting TC with either n-propylenediol or2-methylpropylenediol, the structures of which are shown below, to formthe corresponding diol terephthalate.

[0240] These diol terephthalates were then reacted with EOP to form thecorresponding homopolymers. The homopolymers so formed were then used toproduce the copolymers of the invention in a second reaction with TC, asdescribed above in Example 4.

Example 7 Glass Transition Temperatures for P(BHET-EOP/TC) Copolymers

[0241] By differential scanning calorimetry (DSC), the glass transitiontemperatures (Tg's) of P(BHET-EOP/TC, 80/20) and P(BHET-EOP/TC, 50/50)were determined to be 24.5° C. and 62.2° C. respectively. FIG. 4 showsthe DSC curves for these two polymers. The Tg's of four additionalP(BHET-EOP/TC) copolymers of differing EOP/TC feed ratios weredetermined, and the results were tabulated, as shown below in Table 2:TABLE 2 Glass Transition Temperatures (Tg's) of (BHET-EOP/TC) PolymersRatio of 100/0 95/5 90/10 85/15 80/20 50:50 EOP/TC* Tg (° C.) 19.1 20.721.2 29.8 24.5 62.2

[0242] The Tg increased as the proportion of EOP decreased and theproportion of TC increased.

Example 8 Glass Transition Temperatures for P(BHDPT-EOP/TC) Copolymers

[0243] A study of the influence of an increasing proportion ofterephthaloyl chloride (TC) on the Tg's of P(BHDPT-EOP/TC)polymers wasalso conducted. The results are shown below in Table 3. TABLE 3Influence of EOP/TC Ratio on the Tg of P (BHDPT-EOP/TC) Molar ratio(BHDPT/EOP/TC)* Tg (° C.) 100:100:0 14 100:100:0 19 100:90:10 16100:85:15 24 100:80:20 23 100:75:25 33 100:75:25 49 100:50:50 43

Example 9 Glass Transition Temperatures for Various R Groups

[0244] A study was also conducted showing the effect on glass transitiontemperature (Tg) for copolymers made from the following series of diolshaving varying R groups:

[0245] where R is —CH₂CH₂—; —CH₂CH₂CH₂—; —CH₂CH(CH₃)CH₂—; and—CH₂CH(CH₃)₂CH₂—. The results are shown below in Table 4: TABLE 4Influence of the Changing “R” Group on Tg of Polymer “R” Group StructureTg (° C.) ethylene —CH₂CH₂— 14-19 n-propylene —CH₂CH₂CH₂— −152-methyl-propylene

11 2,2′-dimethyl-propylene

19

[0246] As shown in Table 4, the Tg increased as the size and the degreeof branching of the R group increased. In addition, the polymers changedin physical state as the Tg changed. Specifically, as Tg increased, thepolymers changed from rubbery to fine powders.

Example 10 Solubilities of the Polymers of the Invention

[0247] The solubility in organic solvents was determined for thehomopolymer P(BHET-EOP, 100/0) and for the following block copolymers:

[0248] P(BHET-EOP/TC, 95/5),

[0249] P(BHET-EOP/TC, 90/10),

[0250] P(BHET-EOP/TC, 85/15),

[0251] P(BHET-EOP/TC, 80/20), and

[0252] P(BHET-EOP/TC, 50/50).

[0253] The organic solvents used for the test were chloroform, methylenechloride, N-methylpyrrolidone (NMP), dimethylformamide (DMF) anddimethylsulfoxide (DMSO). The results of these solubility tests aresummarized below in Table 5. TABLE 5 Polymer CHCl₃ CH₂Cl₂ NMP DMF DMSOP(BHET- Easily Easily Good Good Good EOP, soluble soluble solubi-solubi- solubi- 100/0) lity lity lity P(BHET- Easily Easily Good GoodGood EOP/TC, soluble soluble solubi- solubi- solubi- 95/5) lity litylity P(BHET- Easily Easily Good Good Good EOP/TC, soluble solublesolubi- solubi- solubi- 90/10) lity lity lity P(BHET- Rela- Rela- GoodGood Good EOP/TC, tively tively solubi- solubi- solubi- 85/15) solublesoluble lity lity lity P(BHET- Rela- Rela- Good Good Good EOP/TC, tivelytively solubi- solubi- solubi- 80/20) soluble soluble lity lity lityP(BHET- Not Not Soluble Soluble Soluble EOP/TC, soluble soluble withwith with 50/50) heating heating heating

[0254] The results showed that the solubility of these polymers inorganic solvents increased as the EOP/TC ratio increased.

Example 11 Viscosities of the Polymers

[0255] The intrinsic viscosities of a series of P(BHET-EOP/TC) polymersof varying feed ratios were measured in chloroform (CH₃C1) at 40° C. ina Ubbelohde viscometer. The results are shown below in Table 6. TABLE 6Intrinsic Viscosities of P(BHET-EOP/TC) Polymers Ratio of 100/0 95/590/10 85/15 80/20 50:50 EOP/TC* [η] .081 .089 .148 .146 0.180 N.D.^(†)(dL/g)

Example 12 In Vitro Degradation

[0256] Films of P(BHET-EOP/TC, 80/20) and P(BHET-EOP/TC, 85/15) weremade by solution casting methods and were dried under vacuum for twodays. Discs 1 mm in thickness and 6 mm in diameter were cut from thesefilm sheets. Three discs of each copolymer were placed in 4 mL ofphosphate buffer saline (PBS) (0.1M, pH 7.4) at 37° C. The discs weretaken out of the PBS at different points in time, washed with distilledwater, and dried overnight.

[0257] The samples were analyzed for change in molecular weight andweight loss over time, as shown in FIGS. 7A and 7B. The weight averagemolecular weight of P(BHET-EOP/TC, 80/20) decreased about 20% in threedays. After 18 days, the P(BHET-EOP/TC, 85/15) and P(BHET-EOP/TC, 80/20)discs had lost about 40% and 20% in mass respectively.

[0258] This data demonstrated the feasibility of fine-tuning thedegradation rate of the copolymers and confirmed that the copolymersbecame more hydrolytically labile as the phosphate component (EOP) wasincreased.

[0259] The same process was repeated for the P(BHDPT-EOP) copolymershaving different feed ratios of EOP to TC. FIG. 6 is a graphicrepresentation of the degree of degradation, as measured by change inmolecular weight, over time for the homopolymer P(BHDPT-EOP) and thefollowing block copolymers:

[0260] P(BHDPT-EOP/TC, 85/15),

[0261] P(BHDPT-EOP/TC, 75/25), and

[0262] P(BHDPT-EOP/TC, 50/50).

Example 13 In Vivo Degradation of P(BHET-EOP/TC) Copolymer andPaclitaxel Release In Vitro

[0263]FIGS. 7A and 7B shows the in vivo degradation of P(BHET-EOP/TC,80/20), as measured by weight loss. FIG. 7C shows paclitaxel releasefrom film in vitro.

Example 14 In Vitro Biocompatability/Cytotoxicity of P(BHET-EOP/TC,80/20)

[0264] The cytotoxicity of P(BHET-EOP/TC, 80/20) copolymer was assessedby culturing human embryonic kidney (HEK) cells on a cover slip that hadbeen coated with the copolymer P(BHET-EOP/TC, 80/20). As a control, HEKcells were also cultured on a coverslip coated with TCPS. The cellscultured on the copolymer-coated cover slip exhibited normal morphologyat all times and proliferated significantly in 72 days, as compared to aconsiderably lower amount when identical HEK cells were cultured onTCPS.

Example 15 In Vivo Biocompatibility of P(BHET-EOP/TC, 80/20)

[0265] A 100 mg polymer wafer was formed from P(BHET-EOP/TC, 80/20) and,as a reference, a copolymer of lactic and glycolic acid (75/25, “PLGA”)known to be biocompatible. These wafers were inserted between musclelayers of the right limb of adult SPF Sprague-Dawley rats underanesthesia. The wafers were retrieved at specific times, and thesurrounding tissues were prepared for histopathological analysis by acertified pathologist using the following scoring: Score Level ofIrritation 0 No Irritation  0-200 Slight Irritation 200-400 MildIrritation 400-600 Moderate Irritation More than 600 Severe Irritation

[0266] The results of the histopathological analysis are shown below inTable 7. TABLE 7 Inflammatory Response at Site of Implantation (i.m.) 37 14 1 2 3 Polymer Days Days Days Mo. Mos. Mos. P(BHET- 151 116 163 9860 35 EOP/TC, 80/20) PLGA 148 98 137 105 94 43 (75/25)

[0267] The phosphoester copolymer P(BHET-EOP/TC, 80/20) was shown tohave an acceptable biocompatability similar to that exhibited by thePLGA reference wafer.

Example 16 Preparation of P(BHET-EOP/TC, 80/20) MicrospheresEncapsulating FITC-BSA

[0268] Microspheres were prepared via adouble-emulsion/solvent-extraction method using FITC-labeled bovineserum albumin (FITC-BSA) as a model protein drug. One hundred AL of anFITC-BSA solution (10 mg/mL) were added to a solution of 100 mg ofP(BHET-EOP/TC, 80/20) in 1 mL of methylene chloride, and emulsified viasonication for 15 seconds on ice. The resulting emulsion was immediatelypoured into 5 mL of a vortexing aqueous solution of 1 polyvinyl alcohol(PVA) and 5% NaCl. The vortexing was maintained for one minute. Theresulting emulsion was poured into 20 mL of an aqueous solution of 0.3%PVA and 5% NaCl, which was being stirred vigorously. Twenty-five mL of a2% isopropanol solution was added, and the mixture was kept stirring forone hour to ensure complete extraction. The resulting microspheres werecollected via centrifugation at 3000×g, washed three times with water,and lyophilized. Empty microspheres were prepared in the same way exceptthat water was used as the inner aqueous phase.

[0269] These preparation conditions had been optimized for increasedencapsulation efficiency, improved microsphere morphology, and minimalburst release. The resulting microspheres were mostly between 5 and 20μm in diameter and exhibited a smooth surface morphology. FIG. 8 showsthe size and smoothness of the microspheres, as demonstrated by electronmicroscopy.

[0270] The loading level of FITC-BSA was determined by assaying for FITCafter hydrolyzing the microspheres in a 0.5 N NaOH solution overnight.Loading levels were determined by comparison with a standard curve,which had been generated by making a series of FITC-BSA solutions in 0.5N NaOH. Protein loading levels of 1.5, 14.1 and 22.8 wt. % were readilyobtained.

[0271] The encapsulation efficiency of FITC-BSA by the microspheres wasdetermined at different loading levels by comparing the quantity ofFITC-BSA entrapped with the initial amount in solution via fluorometry.As shown below in Table 8, encapsulation efficiencies of 84.6 and 99.6%were obtained. These results showed that encapsulation efficiencies of70-90% would be readily obtainable. TABLE 8 Encapsulation Efficiency andLoading Level of FITC-BSA in P (BHET-EOP/TC, 80/20) High Loading (%)Loading (22.8%) Low Loading (1.5%) Encapsulation Efficiency (%) 99.684.6

[0272] In addition, it was determined by observation with confocalfluorescence microscopy that the encapsulated FITC-BSA was distributeduniformly within the microspheres.

Example 17 Preparation of P(BHDPT-EOP/TC, 50/50) Microspheres ContainingLidocaine

[0273] An aqueous solution of 0.5% w/v polyvinyl alcohol (PVA) wasprepared in a 600 mL beaker by combining 1.35 g of PVA with 270 mL ofdeionized water. The solution was stirred for one hour and filtered. Acopolymer/drug solution was prepared by combining 900 mg ofP(BHDPT-EOP/TC, 50/50) copolymer and 100 mg of lidocaine in 9 mL ofmethylene chloride and vortex-mixing.

[0274] While the PVA solution was being stirred at 800 rpm with anoverhead mixer, the polymer/drug mixture was added dropwise. Thecombination was stirred for one and a half hours. The microspheres thusformed were then filtered, washed with deionized water, and lyophilizedovernight. The experiment yielded 625 mg of microspheres loaded with3.7% w/w lidocaine.

[0275] Lidocaine-containing microspheres were also prepared fromP(BHDPT-HOP/TC, 50/50) by the same process. This experiment yielded 676mg of microspheres loaded with 5.3% w/w lidocaine.

Example 18 In Vitro Release Kinetics of Microspheres Prepared fromP(BHET-EOP/TC, 80/20) Copolymers

[0276] Five mg of P(BHET-EOP/TC, 80/20) microspheres containing FITC-BSAwere suspended in one mL of phosphate buffer saline (PBS) at pH 7.4 andplaced into a shaker heated to a temperature of 37° C. At various pointsin time, the suspension was spun at 3000×g for 10 minutes, and 500 μlsamples of the supernatant fluid were withdrawn and replaced with freshPBS. The release of FITC-BSA from the microspheres was followed bymeasuring the fluorescence intensity of the withdrawn samples at 519 nm.

[0277] Scaling up, 50 mg of P(BHET-EOP/TC, 80/20) microspheres weresuspended in vials containing 10 mL of phosphate buffer saline (PBS).The vials were heated in an incubator to a temperature of 37° C. andshaken at 220 rpm. Samples of the supernatant were withdrawn andreplaced at various points in time, and the amount of FITC-BSA releasedinto the samples was analyzed by spectrophotometry at 492 nm.

[0278] The results indicated that over 80% of the encapsulated FITC-BSAwas released within the first two days, with an additional amount ofabout 5% being released after 10 days in PBS at 37° C. The releasekinetics of FITC-BSA from P(BHET-EOP/TC, 80/20) microspheres atdifferent loading levels are shown in FIG. 11.

Example 19 In Vitro Release Kinetics of Microspheres Prepared fromP(BHDPT-EOP/TC, 50/50) Copolymers

[0279] Approximately 10 mg of P(BHDPT-EOP/TC, 50/50) microspheres loadedwith lidocaine were placed in PBS (0.1 M, pH 7.4) at 37° C. on a shaker.Samples of the incubation solution were withdrawn periodically, and theamount of lidocaine released into the samples was assayed by HPLC. FIGS.10 and 11 show the resulting release kinetics.

[0280] The same process was followed for microspheres prepared fromP(BHDPT-HOP/TC, 50/50). FIGS. 10 and 11 also show the release kineticsof lidocaine from these microspheres.

Example 20 In Vitro Cytotoxicity Assay of Copolymer on Cells

[0281] P(BHET-EOP/TC, 80/20) microspheres were added to 96-well tissueculture plates at different concentrations. The wells were then seededwith human gastric carcinoma cells (GT3TKB) at a density of 10⁴cells/well. The cells were incubated with the microspheres for 48 hoursat 37° C. The resulting cell proliferation rate was analyzed by MTTassay and plotted as % relative growth vs. concentration of copolymermicrospheres in the tissue culture well. The results are shown in FIG.14.

Example 21 Toxicity Assay of Polymer-Degradation Products on GT3TKBTumor Cells

[0282] About 100-150 mg of each of the following polymers were degradedseparately in 20 mL of 1M NaOH at 37° C. for 1-2 days:

[0283] PLLA (Mw=14,000)

[0284] P(BHET-EOP)

[0285] PCPP:SA (20:80)

[0286] Poly(L-lysine) (Mw=88,000)

[0287] Complete degradation was observed for all of the polymers. Thesolution was then neutralized with 20 mL of 1M HCl.

[0288] About 200 μL of various concentrations of the degraded polymerproducts were placed in 96-well tissue culture plates and seeded withhuman gastric carcinoma cells (GT3TKB) at a density of 10⁴/well. Thedegraded polymer products were incubated with the GT3TKB cells for 48hours. The results of the assay were plotted as k relative growth vs.concentration of degraded polymer in the tissue-culture well and areshown in FIG. 13.

[0289] An additional toxicity assay was conducted with microspheresprepared from the monomer BHET and from the homopolymer BHET-EOP, andcompared with microspheres prepared from LA and PLLA. The results of theassay were plotted as % relative growth vs. concentration of thepolymers or microspheres in a tissue-culture cell and are shown in FIG.14.

Example 22 Synthesis of Poly(L-lactide-co-ethyl-phosphate)[Poly(LAEG-EOP)]

[0290]

[0291] 20 g (0.139 mole of (3S)-cis-3,6-dimethyl-1,4-dioxane-2,5-dione(L-lactide) (obtained from Aldrich Chemical Company, recrystallized withethyl acetate, sublimed, and recrystallized with ethyl acetate again)and 0.432 g (6.94 mmole) of ethylene glycol (99.8%, anhydrous, fromAldrich) were placed in a 250 mL round-bottomed flask flushed with driedargon. The flask was closed under vacuum and placed in an oven heated to140° C. The flask was kept at this temperature for about 48 hours withoccasional shaking.

[0292] The flask was then filled with dried argon and placed in oil bathheated to 135° C. Under an argon stream, 1.13 g of ethylphosphorodichloridate was added with stirring. After one hour ofstirring, a low vacuum (about 20 mm Hg) was applied to the system, andit was allowed to stand overnight. One hour before work-up, a highvacuum was applied. After cooling, the polymer was dissolved in 200 mLof chloroform and quenched into one liter of ether twice to an off-whiteprecipitate, which was dried under vacuum.

[0293] It was confirmed by NMR spectroscopy that the polymer obtainedwas the desired product, poly(L-lactide-co-ethyl-phosphate)[P(LAEG-EOP)], as shown in FIGS. 6 and 7.

Example 23 Properties of P(LAEG-EOP)

[0294] A P(LAEG-EOP) polymer where (x or y)/n=10:1 was prepared asdescribed above in Example 22. The resulting poly(phosphoester-co-ester)polymer was analyzed by GPC using polystyrene as a standard, and theresulting graph established an Mw of 33,000 and an Mn of 4800, as shownin FIG. 16.

[0295] The viscosity was measured in chloroform (CH₃Cl) at 40° C. anddetermined to be 0.315 dL/g. The polymer was soluble in ethyl acetate,acetone, acetonitrile, chloroform, dichloromethane, tetrahydrofuran,N-methylpyrrolidone, dimethylformamide, and dimethyl sulfoxide. Thepolymer formed a brittle film, and the Tg was determined by DSC to be51.5° C., as shown in FIGS. 17A and 17B.

Example 24 Synthesis of Poly(L-lactide-co-hexyl-phosphate)

[0296] [Poly(LAEG-HOP)]

[0297] A second poly(L-lactide-phosphate) having the followingstructure:

[0298] was also prepared by the method described in Example 22, exceptthat hexyl phosphorodichloridate (“HOP”) was substituted for EOP (ethylphosphorodichloridate).

Example 25 Properties of P(LAEG-EOP) and P(LAEG-HOP)

[0299] The weight-average molecular weight (Mw) of thephosphoester-co-ester polymer of Example 22, P(LAEG-EOP), and thepolymer of Example 24, P(LAEG-HOP), were first determined by gelpermeation chromatography (GPC) with polystyrene as the calibrationstandard, as shown in FIG. 18. Samples of each were then allowed toremain exposed to room temperature air to test for ambient, unprotectedstorage capability. After one month, the Mw was again determined foreach polymer. The results (plotted in FIG. 19) showed that, while the Mwfor p(LAEG-EOP) was reduced by about one-third after a month ofunprotected ambient conditions, the Mw for p(LAEG-HOP) remained fairlyconstant, even showing a slight increase. See also FIG. 20.

[0300] Discs for degradation studies were then fabricated from eachpolymer by compression molding at 50° C. and a pressure of 200 MPa. Thediscs were 4 mm in diameter, 1.5 mm in thickness, and 40 mg in weight.The degradation studies were conducted by placing the discs in 4 mL of0.1M PBS (pH 7.4) at 37° C. Duplicate samples were removed at differenttime points up to eight days, washed with distilled water, and driedunder vacuum overnight. Samples were analyzed for weight loss andmolecular weight change (GPC), and the results are shown in FIGS. 4A,4B, 10A and 10B. Both polymers, P(LAEG-EOP) and P(LAEG-HOP),demonstrated favorable degradation profiles.

Example 26 In Vivo Biocompatibility of P(LAEG-EOP)

[0301] A 100 mg polymer wafer was formed from P(LAEG-EOP) and, as areference, a copolymer of lactic and glycolic acid [“PLGA (RG755)”]known to be biocompatible. These wafers were inserted between musclelayers of the right limb of adult SPF Sprague-Dawley rats underanesthesia. The wafers were retrieved at specific times, and thesurrounding tissues were prepared for histopathological analysis by acertified pathologist using the following scoring: Score Level ofIrritation 0 No Irritation  0-200 Slight Irritation 200-400 MildIrritation 400-600 Moderate Irritation More than 600 Severe Irritation

[0302] The results of the histopathological analysis are shown below inTable 9. TABLE 9 Inflammatory Response at Site of Implantation (i.m.) 37 14 1 2 3 Polymer Days Days Days Mo. Mos. Mos. P(LAEG- 130 123 180 198106 99 EOP) PLGA 148 98 137 105 94 43 (RG755)

[0303] See also FIG. 23. The phosphoester copolymer P(LAEG-EOP) wasshown to have an acceptable biocompatability similar to that exhibitedby the PLGA reference wafer.

[0304] Similar tests were done after intramuscular injection ofmicrospheres into male S-D rats, tabulating implant site macrophagecounts, as well as irritation scores, as shown below: 3 Day 7 Day 14 Day31 Day Ir- Ir- Ir- Ir- rita- rita- rita- rita- Polymer # tion # tion #tion # tion p(BHET- 247 Mild 298 Mild 196 Sl. 32 Sl. EOP/TC) 80/20p(BHET- 445 Mod. 498 Mod. 406 Mod. 38 Sl. EOP/TC) 82.5/ 17.5 p(BHET- 161Sl. 374 Mild 586* Mod. 274 Mild EOP/TC) 85/15 p(CHDM- 399 Mild 169 Sl.762 Sev. 607 Sev. HOP) p(BHET- 206 Mild 476 Mod. 557 Mod. 72 Sl. EOP/TC)90/10 P(DAPG- 360 Mild 323 Mild 569 Mod. 96 Sl. EOP) 1:10 PLGA 419 Mod.331 Mod. 219 Mild 150 Sl. (RG755) Control 219 Mild — — — — — — (no poly-mer)

[0305] Still further tests were done after subcutaneous injection intomale S-D rats, tabulating implant site macrophage counts, as well asirritation scores, as shown below: 7 Day 14 Day 31 Day Ir- Ir- Ir- rita-rita- rita- Group # tion # tion # tion Vehicle only 0 — 0 — 0 — (0.7 ml)(n = 3) Acetic Acid 208 Mild 166 Sl. 20 Sl. (0.7 ml) (n = 3) p(dl)Lactic 302 Mild 37 Sl. 0 — Acid (89 g/kg) (0.7 ml) (n = 3) p(DAPG-HOP)355 Mild 192 Sl. 101 Sl. (89 mg/kg) (0.7 ml) (n = 6) p(CHDM- 652 Sev.352 Mild 633 Sev. HOP) (89 mg/kg) (0.7 ml) (n = 6) P(BHET- 325 Mild 423Mod. 197 Sl. EOP/TC) (89 mg/kg) (0.7 ml) (n = 6) Vehicle 65 Sl. 0 — 0 —(2.0 ml) (n = 3) Acetic Acid 267 Mild 334 Mild 32 Sl. (2.0 ml) (n = 3)p(dl) Lactic 85 Sl. 18 Sl. 279 Mild Acid (267 g/kg) (2.0 ml) (n = 3)p(DAPG-HOP) 386 Mild 273 Mild 279 Mild (267 mg/kg) (2.0 ml) (n = 6)p(CHDM- 471 Mod. 599 Mod. 618 Sev. HOP) (267 mg/kg) (2.0 ml) (n = 6)P(BHET- 292 Mild 327 Mild 178 Sl. EOP/TC) (267 mg/kg) (2.0 ml) (n = 6)

Example 27 Preparation of Copolymer Microspheres Containing FITC-BSAwith 10k Theoretical Loading Level

[0306] One hundred mL of FITC-BSA solution (100 mg/mL dissolved inwater) was added to a solution of 100 mg of P(LAEG-EOP) in 1 mL ofmethylene chloride, and emulsified via sonication for 15 seconds on ice.The resulting emulsion was immediately poured into 5 mL of vortexing a1% solution of polyvinyl alcohol (PVA) in 5% NaCl, and vortexing wasmaintained for one minute. The emulsion thus formed was then poured into20 mL of a 0.3% PVA solution in 5% NaCl, which was being stirredvigorously. Twenty five mL of a 2% solution of isopropanol was added,and the mixture was kept stirring for one hour to ensure completeextraction. The resulting microspheres were collected via centrifugationat 3000×g, washed 3 times with water, and freeze dried.

[0307] Different formulations of microspheres were made by using as thesecond aqueous phase a 5% NaCl solution or a 5% NaCl solution alsocontaining 1% PEG 8000. Yet another technique was used in evaporatingthe solvent by stirring the mixture overnight, thus forming microspheresby solvent evaporation.

Example 28 Estimation of Encapsulation Efficiency and Loading Level

[0308] The loading level of FITC-BSA was determined by assaying for FITCafter hydrolyzing the microspheres with 0.5 N NaOH overnight. The amountof FITC-BSA was compared with a standard curve that had been generatedby making a series of FITC-BSA solutions in 0.5 N NaOH. Theencapsulation efficiency of the microspheres was determined by comparingthe quantity of FITC-BSA entrapped with the initial amount in solutionvia fluorometry. The encapsulation efficiency (i) and loading level (%)of FITC-BSA are shown in Table 10 below. TABLE 10 EncapsulationEfficiency and Loading Level of FITC-BSA High Loading (%) Loading(24.98%) Low Loading (1.5%) Encapsulation Efficiency (%) 98.10 91.70

Example 29 Cytotoxicity of the Copolymer

[0309] Microspheres containing P(LAEG-EOP) were added to 96-well tissueculture plates at different concentrations. Human gastric carcinomacells (GT3TKB) were then seeded at a rate of 10⁴ cells/well. The cellswere then incubated with the microspheres in the wells for 48 hours at37° C. The cell proliferation rate was analyzed by MTT assay, and theresults were plotted as % relative growth vs. concentration of copolymermicrospheres in the tissue culture well, as shown in FIG. 24.

Example 30 Effect of Fabrication Method on the Release of FITC-BSA fromMicrospheres

[0310] Fifty mg of microspheres of a polymer of the invention weresuspended in vials containing 10 mL of PBS, and the vials were shaken inan incubator at 37° C. and at a rate of 220 rpm. The supernatant fluidwas replaced at various time points, and the amount of FITC-BSA releasedwas analyzed by spectrophotometry at 492 nm. The results were plotted as% cumulative release of FITC-BSA from the microspheres vs. time inhours, as shown in FIG. 25.

Example 31 Preparation of P(LAEG-EOP) Microspheres Containing LidocaineUsing Polyvinyl Alcohol as the Non-Solvent Phase

[0311] A solution of 0.5% w/v polyvinyl alcohol (PVA) in deionized watersolution was prepared in a 600 mL beaker by combining 1.05 g of PVA with210 mL of deionized water. The solution was stirred for one hour andfiltered. A polymer/drug solution was prepared by combining 630 mg ofpolymer and 70 mg of lidocaine in 7 mL of methylene chloride and mixingby vortex. The PVA solution was mixed at 500 rpm with an overhead mixer,and the polymer/drug solution was added dropwise. After 30 minutes ofmixing, 200 mL of cold deionized water was added to the stirring PVAsolution. The resulting mixture was stirred for a total of 3.5 hours.The microspheres formed were filtered off, washed with deionized water,and lyophilized overnight.

[0312] Microspheres loaded with 4.2% w/w lidocaine were thus obtained.Approximately 10 mg of microspheres were placed in a phosphate buffersaline (0.1M, pH 7.4) at 37° C. on a shaker and sampled regularly. Theresults were plotted as % lidocaine released vs. time in days, as shownin FIG. 25.

Example 32 Synthesis of P(DAPG-EOP)

[0313] The d,l racemic mixture of poly(L-lactide-co-propyl-phosphate)[“P(DAPG-EOP)”] was prepared as follows:

[0314] The product was obtained as a white solid soluble in organicsolvents. Depending on reaction conditions, different intrinsicviscosities and different molecular weights were obtained, as shownbelow in summary form: Base(s) Reaction Time/Temp Eq EOPCl₂ Mw IV 3.0 eqReillex 18 hrs/ 1.05 — 0.06 reflux 3.0 eq Reillex 40 hrs/ 1.05 — 0.06reflux 3.0 eq Reillex & 18 hrs/ 1.05 — 0.08 0.1% (w/w) reflux DMAP 3.0eq Reillex 18 hrs/ 1.00 — 0.06 reflux 2.5 eq 15 mins/ 1.05 — 0.42 TEA;0.5 room eq DMAP temp. 2.5 eq 18 hrs/ 1.05 — 0.27 TEA; 0.5 reflux eqDMAP 2.5 eq about 2.5 1.05 — 0.39 TEA; 0.5 days/ eq DMAP reflux 2.5 eq 1h/4° C.; 1.01 — 0.06 TEA; 0.1 2 h/room eq DMAP temp. 2.5 eq 1 h/4° C.;1.01 91,100 0.47 TEA; 0.5 2 h/room eq DMAP temp. 2.5 eq 1 h/4° C.; 1.0195,900 0.42 TEA; 0.5 2 h/room (Mn eq DMAP temp. 44,200; Mw/Mn 2.2) 1.1eq 1 h/4° C.; 1.01 — 0.08 DMAP 2 h/room temp. 1.5 eq 1 h/4° C.; 1.01 —0.23 TEA; 0.5 2 h/room eq DMAP temp. 2.5 eq 1 h/4° C.; 1.00 28,400 0.25TEA; 0.5 17 h/room eq DMAP temp. 2.5 eq 1 h/4° C.; 1.00 26,800 0.23 TEA;0.5 2 h/room (Mn eq DMAP temp. 12,900; Mw/Mn 2.1) 2.5 eq 1 h/4° C.; 1.0114,700 0.16 TEA; 0.5 2 h/room eq DMAP temp. 2.5 eq 1 h/4° C.; 1.0132,200 0.32 TEA; 0.5 2 h/room (Mn eq DMAP temp. 13,000; Mw/Mn 2.5) 3.0eq 1 h/4° C.; 1.00 — 0.20 DMAP 2 h/room temp. 2.5 eq 1 h/4° C.; 1.00 —0.22 TEA; 0.5 2 h/room eq DMAP temp.

Example 33 Preparation of P(DAEG-EOP) Microspheres with Lidocaine UsingSilicon Oil as the Non-Solvent Phase

[0315] Two percent sorbitan-trioleate, which is commercially availablefrom Aldrich under the tradename Span-85, in silicon oil was prepared ina 400 mL beaker by combining 3 mL of Span-85 with 150 mL of silicone oiland mixing with an overhead stirrer set at 500 rpm. A d,l racemicmixture of poly(L-lactide-co-ethyl-phosphate) P(DAEG-EOP) polymer/drugsolution was prepared by dissolving 400 mg of the polymer prepared abovein Example 33, and 100 mg of lidocaine in 4.5 mL of methylene chloride.The resulting polymer/drug solution was added dropwise to the siliconeoil/span mixture with stirring. The mixture was stirred for an hour and15 minutes. The microspheres thus formed were filtered off and washedwith petroleum ether to remove the silicone oil/span mixture, andlyophilized overnight.

[0316] 450 mg of microspheres loaded with 7.6% w/w lidocaine were thusobtained. Approximately 10 mg of microspheres were placed in phosphatebuffer saline (0.1M, pH 7.4) at 37° C. on a shaker and sampledregularly. The results were plotted as % lidocaine released vs. time indays.

[0317] Similar data for P(DAPG-EOP) microspheres containing paclitaxelwas obtained, as shown in FIGS. 26A, 26B, 26C, 26D, 26E and 26F.

Example 34 Biocompatibility of Poly(Phosphoester) Microspheres in MousePeritoneal Cavity

[0318] The biocompatibility of biodegradable poly(phosphoester)microspheres of the invention was tested as follows:

[0319] Three 30 mg/mL samples of lyophilizedpoly(L-lactide-co-ethyl-phosphate) microspheres were prepared, the firsthaving diameters greater than 75 microns, the second having diameterswithin the range of 75-125 microns, and the third having diameterswithin the range of 125-250 microns Each sample was injectedintra-peritoneally into a group of 18 female CD-1 mice having a startingbody weight of 25 g. Animals in each group were weighed, sacrificed, andnecropsied at 2, 7 and 14 days, and at 1, 2 and 3 months. Any lesionsdetected during the necropsy were graded on a scale of 0 to 4, with 0indicating no response to treatment and 4 indicating a severe responseto treatment.

[0320] Inflammatory lesions were observed to be restricted to anassociation with the microspheres on peritoneal surfaces or within fattissue, and were compatible with foreign body isolation andencapsulation. Focal to multifocal supportive peritoneal steatitis withmesothelial hyperplasia was observed at 2-7 days, but gradually resolvedby macrophage infiltration, the formation of inflammatory giant cells,and fibrous encapsulation of the microspheres at later sacrifices.Occasional adherence of microspheres to the liver and diaphragm, withassociated inflammatory reaction, was also seen. Lesions related tomicrospheres were not seen within abdominal or thoracic organs.Microspheres, which were detected throughout the duration of the study,appeared transparent at early sacrifices but, at later times, developedcrystalline material internally. No effects on body growth wereobserved. The peritoneal reaction was observed to be limited to areasdirectly adjacent to the microspheres with no apparent deleteriouseffects on major thoracic or abdominal organs.

[0321] Similar intraperitoneal injection of DAPG-EOP into male andfemale S-D rats gave the following results: Dose Initial No. CumulativeLevel Test in Test Mortality^(a) (mg/kg) Material M F M F 0 10% 25 25 00 Dextran 40 in 0.9% Saline 30 DAPG-EOP 25 25 1 0 100 DAPG-EOP 25 25 0 0300 DAPG-EOP 25 25 0 0

Example 35 Synthesis of the Poly(Phosphoester) P(trans-CHDM-HOP)

[0322]

[0323] Under an argon stream, 10 g of trans-1,4-cyclohexane dimethanol(CHDM), 1.794 g of 4-dimethylaminopyridine (DMAP), 15.25 ml (14.03 g) ofN-methyl morpholine (NMM), and 50 ml of methylene chloride, weretransferred into a 250 ml flask equipped with a funnel. The solution inthe flask was cooled down to −15° C. with stirring, and a solution of15.19 g of hexyl phosphorodichloridate (HOP) in 30 ml of methylenechloride was added through the funnel. The temperature of the reactionmixture was raised to the boiling point gradually and maintained atreflux temperature overnight.

[0324] The reaction mixture was filtered, and the filtrate wasevaporated to dryness. The residue was re-dissolved in 100 ml ofchloroform. This solution was washed with 0.1 M solution of a mixture ofHCl and NaCl, dried over anhydrous Na₂SO₄, and quenched into 500 ml ofether. The resulting flowable precipitate was collected and dried undervacuum to form a clear pale yellow gelatinous polymer with the flowcharacteristics of a viscous syrup. The yield for this polymer was70-80%. The structure of P(trans-CHDM-HOP) was ascertained by ³¹P-NMRand ¹H-NMR spectra, as shown in FIG. 27, and by FT-IR spectra. Themolecular weights (Mw=8584; Mn=3076) were determined by gel permeationchromatography (GPC), as shown in FIG. 28, using polystyrene as acalibration standard.

Example 36 Synthesis of the Poly(Phosphoester) P(Cis & Trans-CHDM-HOP)

[0325] Poly(phosphoester) P(cis/trans-1,4-cyclohexane-dimethanol hexylphosphate) was prepared by following the procedure described above inExample 34 except that a mixture of cis- andtrans-1,4-cyclohexanedimethanol was used as the starting material. Asexpected, the product cis-/trans-P(CHDM-HOP) was less viscous than thetrans isomer obtained in Example 34.

Example 37 Synthesis of Low Molecular Weight P(CHDM-HOP)

[0326] Under an argon stream, 10 g of trans-1,4-cyclohexane dimethanol(CHDM), 15.25 mL (14.03 g) of N-methyl morpholine (NMM), and 50 mL ofmethylene chloride were transferred into a 250 mL flash equipped with afunnel. The solution in the flask was cooled down to −40° C. withstirring. A solution of 15.19 g of hexyl phosphoro-dichloridate (HOP) in20 mL of methylene chloride was added through the funnel, and anadditional 10 mL of methylene chloride was used to flush through thefunnel. The mixture was then brought up to room temperature graduallyand kept stirring for four hours.

[0327] The reaction mixture was filtered, and the filtrate wasevaporated to dryness. The residue was re-dissolved in 100 ml ofchloroform. This solution was washed with 0.5 M mixture of HCl-NaClsolution, washed with saturated NaCl solution, dried over anhydrousNa₂SO₄, and quenched into a 1:5 ether-petroleum mixture. The resultingoily precipitate was collected and dried under vacuum to form a clear,pale yellow viscous material. The structure of the product was confirmedby ¹H-NMR, ³¹P-NMR and FT-IR spectra.

Example 38 Synthesis of the Poly(Phosphoester) P(trans-CHDM-BOP)

[0328]

[0329] Under an argon stream, 10 g of trans-1,4-cyclohexane dimethanol(CHDM), 0.424 g (5%) of 4-dimethylamino-pyridine (DMAP), 15.25 mL (14.03g) of N-methyl morpholine (NMM) and 50 mL of methylene chloride weretransferred into a 250 mL flask equipped with a funnel. The solution inthe flask was cooled down to −40° C. with stirring. A solution of 13.24g of butyl phosphoro-dichloridate (BOP) in 20 mL of methylene chloridewas added through the funnel, with an additional 10 mL of methylenechloride being used to flush through the funnel. The mixture was heatedto the boiling point gradually, and kept refluxing for four hours. Thereaction mixture was filtered, and the filtrate was evaporated todryness, taking care to keep the temperature below 60° C. The residuewas redissolved in 100 mL of chloroform. The solution formed was washedwith 0.5 M of HCl-NaCl solution and saturated NaCl solution, dried overanhydrous Na₂SO₄, and quenched into a 1:5 ether-petroleum mixture. Theresulting oily precipitate was collected and dried under vacuum toproduce a clear, pale yellow viscous material.

Example 39 Rheological Properties of P(Trans-CHDM-HOP)

[0330] P(trans-CHDM-HOP) remained in a flowable gel-like state at roomtemperature. The polymer exhibited a steady viscosity of 327 Pa·s at 25°C. (shown in FIG. 29B), and a flowing active energy of 67.5 KJ/mol(shown in FIG. 29A).

Example 40 In Vitro Cytotoxicity of P(Trans-CHDM-HOP)

[0331] Cover slips were coated with P(trans-CHDM-HOP) by a spin coatingmethod. The coated coverslips were then dried and sterilized by UVirradiation overnight under a hood. A P(trans-CHDM-HOP)-coated coverslip was placed at the bottom of each well of a 6-well plate. 5×10⁵HEK293 (human embryonic kidney) cells were plated into each well andcultured for 72 hours at 37° C. The resulting cell morphology wasexamined, using tissue culture polystyrene (TCPS) as a positive control.The cells growing on the P(CHDM-HOP) surface proliferated at a slightlyslower rate, as shown by FIG. 30. However, the morphology of cells grownon the polymer surface was similar to the morphology of cells grown onthe TCPS surface.

Example 41 In Vitro Degradation of P(CHDM-Alkyl Phosphates)

[0332] Each of the following poly(phosphate)s was prepared as describedabove: TABLE 11 Polymer Side Chain P (CHDM-HOP) —O-hexyl group P(CHDM-BOP) —O-butyl group P (CHDM-EOP) —O-ethyl group

[0333] A sample of 50 mg of each polymer was incubated in 5 mL of 0.1 M,pH 7.4 phosphate buffer saline (PBS) at 37° C. At various points intime, the supernatant was poured out, and the polymer samples werewashed three times with distilled water. The polymer samples were thenextracted with chloroform, and the chloroform solution was evaporated todryness. The residue was analyzed for weight loss by comparing with theoriginal 50 mg sample. FIG. 31 graphically represents the effect of theside chain structure on the in vitro degradation rate ofpoly(phosphates) in PBS.

Example 42 In Vitro Release Profile of Protein by P(CHDM-HOP)

[0334] The polymer P(CHDM-HOP) was blended with the protein FITC-BSA(bovine serum albumin, a protein, tagged with the fluorescent labelFITC; “FITC-BSA”) at a 2:1 (w/w) ratio (33% loading). Measured amounts(66 mg or 104 mg) of the polymer-protein blend were placed into 10 ml ofPBS (0.1M, pH 7.4), a phosphate buffer. At regular intervals (roughlyevery day), the samples were centrifuged, the supernatant buffer wasremoved and subjected to absorption spectroscopy (501 nm), and freshamounts of buffer were added to the samples. The resulting releasecurve, plotting the cumulative percentage of FITC-BSA released versustime, is graphically represented in FIG. 32. The loading level of theprotein in both cases was 33 weight %.

Example 43 In Vitro Protein Release Profile at Various Loading Levels

[0335] FITC-BSA was blended with P)(CHDM-HOP) at different loadinglevels (1%, 10% and 30%) at room temperature until the mixture formed ahomogenous paste. 60 mg of the protein-loaded polymer paste was placedin 6 mL of 0.1 M phosphate buffer and constantly shaken at 37° C. Atvarious time points, samples were centrifuged, and the supernatant wasreplaced with fresh buffer. The released FITC-BSA in the supernatant wasmeasured by UV spectrophotometry at 501 nm. FIG. 7 graphicallyrepresents the in vitro release kinetics of FITC-BSA as a function ofloading level.

Example 44 Effect of Side Chain Structure on In Vitro Protein ReleaseKinetics of FITC-BSA

[0336] The following three polymers were prepared as described above:

[0337] P(CHDM-EOP)

[0338] P(CHDM-BOP) and

[0339] P(CHDM-HOP)

[0340] FITC-BSA was blended with each polymer at a 10% loading level atroom temperature to form a homogenous paste. 0.60 mg of theprotein-loaded polymer paste was placed in 6 mL of 0.1 M phosphatebuffer with constant shaking at 37° C. At various time points, sampleswere centrifuged, and the supernatant was replaced with fresh buffer.The released FITC-BSA in the supernatant was measured by UVspectrophotometry at 501 nm. FIG. 34 graphically represents the in vitroeffect of side chain variations on the protein release kinetics ofFITC-BSA at 10 loading level.

Example 45 In Vitro Small Molecular Weight Drug Release from P(CHDM-HOP)

[0341] A P(CHDM-HOP) paste containing doxorubicin, cisplatin, or5-fluorouracil, was prepared by blending 100 mg of P(CHDM-HOP) with 1 mgof the desired drug at room temperature, respectively. An aliquot of 60mg of the drug-loaded paste was placed in 6 mL of 0.1 M phosphate bufferat 37° C. with constant shaking, with three samples being done for eachdrug being tested. At various time points, the supernatant was replacedwith fresh buffer solution. The levels of doxorubicin and 5-fluorouracilin the supernatant were quantified by UV spectrophotometry at 484 nm and280 nm, respectively. The cisplatin level was measured with an atomicabsorbance spectrophotometer. FIG. 9A shows the release of these lowmolecular weight drugs from P(CHDM-HOP).

[0342]FIG. 9B shows the release of hydrophobic small molecules, such aspaclitaxel, from p(CHDM-HOP).

Example 46 In Vitro Release Profile of Doxorubicin and Cisplatin fromP(CHDM-HOP)

[0343] A paste was made by blending 300 mg of P(CHDM-HOP) with 6 mg ofdoxorubicin and 6 mg of cisplatin at room temperature to form a uniformdispersion. A sample of 100 mg of the paste was incubated in 10 mL ofphosphate buffer (pH 7.4) at 37° C. with shaking. At different timepoints, samples were centrifuged, 9 mL of the supernatant were withdrawnand replaced with fresh buffer. The withdrawn supernatant was assayedspectrophotometrically at 484 nm to determine the amount of doxorubicinreleased into the withdrawn supernatant, and the cisplatin release wasmeasured by atomic absorbance spectrophotometer. FIG. 36 graphicallyrepresents the simultaneous release of cisplatin and doxorubicin fromP(CHDM-HOP).

Example 47 In Vivo Biocompatibility of P(trans-CHDM-HOP)

[0344] The polymer P(trans-CHDM-HOP) was synthesized as described inExample 1. To facilitate injection, ethyl alcohol was added to thepolymer at levels of 10% and 20% by volume to reduce the viscosity.Samples of 25 μL of the polymer alone, 25 μL of the polymer containing10% alcohol, and 25 μL of the polymer containing 20% alcohol, wereinjected into the back muscles of Sprague Dawley rats. Tissues at theinjection sites were harvested at either three or thirteen dayspost-injection, processed for paraffin histology, stained withhematoxylin, eosin dye and analyzed. Medical-grade silicon oil wasinjected into the control group rats.

[0345] Histological examination of the back muscle sections of the ratsinjected with the polymer diluted with ethanol showed no acuteinflammatory response. The level of macrophage presence was comparableto that of the control group, which had been injected with medical-gradesilicon oil, and neutrophils were not present in any of the samplestaken on either the third or thirteenth day.

Example 48 Controlled Delivery of Interleukin-2 and Doxorubicin fromP(CHDM-HOP) in an In Vivo Tumor Model

[0346] Lyophilized interleukin-2 (“IL-2”) was purchased from Chiron,mouse Interferon-γ (“mIFN-γ”) was obtained from Boehringer Mannheim, anddoxorubicin hydrochloride (“DOX”) was obtained from Sigma. C57BL/6 mice,6-8 weeks of age, were obtained from Charles River. The aggressivemelanoma cell line B16/F10 was used to cause tumors in the mice, and thecells were maintained by weekly passages. The polymer P(CHDM-HOP) wassynthesized as described in Example 35.

[0347] Mice were randomly allocated into groups as shown below in Table12. The day of tumor injection with cells of the melanoma cell line wasdenoted as Day 0. Each mouse received a subcutaneous injection of 50 μl(10⁵) tumor cells in phosphate buffer saline (PBS) in the left flank. OnDay 3 or Day 7, the tumor-bearing mice were selectively injected in theright flank with one of the following formulations: (1) a bolus of IL-2,(2) a bolus of DOX, (3) a polymer paste of IL-2, (4) a polymer paste ofDOX, (5) a polymer paste containing both IL-2 and DOX, or (6) a polymerpaste containing both IL-2 and mIFN-γ). A control group and negativecontrol group received no further injections on Day 3 or Day 7.

[0348] The bolus preparation of either IL-2 or DOX was prepared bydissolving an appropriate amount of IL-2 or DOX in 50 Al of isotonicsolution just prior to the injection. The polymer paste formulations ofeither IL-2, DOX, a mixture of both IL-2 and DOX, or a mixture of IL-2and mIFN-γ, were prepared by blending 50 μl of sterilized P(CHDM-HOP)with the drug(s) until homogeneous. TABLE 12 Allocation of Groups ofMice for In Vivo Tumor Model Day of Group Number of Mice InjectionFormulation Control 5 — Nothing Negative 5 — Nothing Control Bolus IL-28 3 0.8 × 10⁶ IU Bolus DOX 8 3 0.5 mg Bolus DOX 8 7 0.5 mg Paste IL-2 103 0.8 × 10⁶ IU Paste IL-2 10 7 0.8 × 10⁶ IU Paste DOX 10 3 0.5 mg PasteDOX 10 7 0.5 mg Paste (IL- 10 3 0.8 × 10⁶ IU + 0.5 mg 2 + DOX) Paste(IL- 10 7 0.8 × 10⁶ IU + 0.5 mg 2 + DOX) Paste (IL- 10 3 10⁶ IU 2 +mIFN- γ)

[0349] On Day 28 and Day 42 of tumor growth, the tumor sizes of thevarious mice were measured. The results are shown below in Table 13,which shows the numerical data for the growth of tumor volumes on Day 28and Day 42 and the number of mice who survived the experiment per druggrouping. Tumor volume was calculated as half the product of the lengthand the square of the width, in accordance with the procedure of Osiekaet al., 1981. TABLE 13 CHDM-HOP Polymer as Carrier for Cytokine and DrugDelivery in Melanoma Model Tumor Volume (mm³ ± SEM*) After Initial TumorInjection Number 28 days 42 days Group of Mice Number of Mice SurvivedControl 5 No tumor No tumor Negative 5   2458 ± 1070.7 5656 Control  4  1 Bolus IL- 8   1946 ± 505.6   3282 ± 1403.3 2 (3d)  8   4 Bolus Dox 81218.9 ± 304.1 3942.5 ± 1818 (3d)  8   5 Bolus Dox 8 1661.2 ± 301.84394.3 ± 741.3 (7d)  8   3 Paste IL- 10  934.1 ± 230   3183 ± 1223.4 2(3d) 10   5 Paste IL- 10 2709.8 ± 397.3  10491 ± 2485.5 2 (7d) 10   3Paste Dox 10   1410 ± 475.3 4648.9 ± 1202.2 (3d)  8   7 Paste Dox 10  1480 ± 287   3915 ± 1739.7 (7d)  9   4 Paste 10  657.3 ± 248.9 3362.8± 1120.1 (IL-2 ± DOX)  8   7 (3d) Paste 10  857.2 ± 243.6 3449.8 ±1285.9 (IL-2 ± DOX)  8   5 (7d) Paste 10 1217.9 ± 168.4 4469.8 ± 2018.7(IL-2 ± mIFN-γ)  9   4 (3d)

[0350] Based on these measurements, the distribution of tumors sizeswere graphically represented in FIG. 37 for Day 28 (four weeks aftertumor implantation) and in FIG. 38 for Day 42 (six weeks after tumorimplantation). The graphs were subdivided into plots according to thedifferent treatments given to the tumor-bearing mice.

[0351] The results on Day 28 showed that, in comparison with the controlgroup (tumor without treatment) and the bolus injection of IL-2, thegroup of mice receiving a polymer/IL-2 paste injection successfullydelayed the tumor's growth. However, for the group of mice not receivinga polymer/IL-2 paste injection until Day 7, the tumor had already becomeof substantial size by Day 7 and, accordingly, a significant reductionin tumor size was not observed.

[0352] Excellent tumor reduction was obtained with the combination ofIL-2 and DOX. The average size of a tumor treated with an injection of apolymer paste containing both IL-2 and DOX was significantly smallerthan the tumor in the control group. Specifically, the average tumorsize for mice receiving the IL-2 and DOX/polymer paste on Day 3 was657.3 mm³, as opposed to 2458 mm³ for the control group. Even whentreatment was delayed until Day 7 of tumor growth, a therapeutic effectcould still be seen with the polymer paste formulation containing bothIL-2 and DOX.

[0353] The results on Day 42 of tumor growth also confirmed that the Day3 injection of polymer paste containing both IL-2 and DOX gave the bestresult in delaying tumor growth. The combined therapy of IL-2 and DOX ina polymer paste of the invention resulted in the occurrence of smallersized tumors in more of the test animals. According to the distributiondata shown in FIG. 15, there were four mice bearing tumors of less than1000 mm³ in the case of the combined IL-2 and DOX polymer paste therapy,as compared with only one mouse inside that range for the polymer pasteinjection of DOX alone. It was also clear that IL-2 alone did notprovide the most desirable effect, as evaluated on the 42nd day of tumorgrowth. Despite the good distribution of small tumor sizes on the 28thday, the long-time survival data appeared to be adversely affected, notonly by the progression of tumor growth at that point, but also by thelack of continued, controlled delivery of IL-2 over a longer timeperiod. With the polymer paste formulation of both IL-2 and DOX, thepolymer degraded slowly, allowing a gradual decrease in the diffusionrate of the therapeutic agent over time.

[0354] However, because of the significant difference of thedistribution in tumor sizes inside each group, the average tumor size asseen in Table 13 did not provide a complete picture. A fullerappreciation of the significance of the treatments of the invention canbe gained by comparing data from the distribution graph of FIG. 38 whichshows the dispersity in tumor sizes six weeks after tumor implantation,with the survival curve shown in FIG. 39, which shows the massive deathof mice in all groups before the Day 42 measurement, except for thegroups of animals that had received the 3rd day injection of pastecontaining either DOX alone or the combination of IL-2 and DOX. Thus,the data, taken as a whole, shows that the combined therapy of IL-2 andDOX in the paste both significantly delayed tumor growth and extendedlife.

[0355] Early deaths about 3-4 days after the injections of theDOX-containing polymer paste were thought to be due, at least in part,to the toxic effect of DOX causing the deaths of the weaker animals.Corresponding injections of bolus DOX did not produce early death,probably because of the rapid distribution and clearance from the bodyof the bolus-injected DOX.

Example 49 Incorporating Paclitaxel into P(CHDM-HOP) or P(CHDM-EOP)

[0356] 100 mg of each of the polymers p(CHDM-HOP) and p(CHDM-EOP) wasdissolved in ethanol at a concentration of about 50%. After the polymerwas completely dissolved, 5 mg of paclitaxel powder (a chemotherapeuticdrug) was added to the solution and stirred until the powder wascompletely dissolved.- This solution was then poured into ice water toprecipitate the polymer composition. The resulting suspension wascentrifuged, decanted, and lyophilized overnight, to obtain a viscousgelatinous product.

Example 50 In Vitro Release of Paclitaxel from P(CHDM-HOP) andP(CHDM-EOP)

[0357] In a 1.7 mL plastic micro centrifuge tube, 5 mg of both of thepaclitaxel polymer formulations of Example 20 to be tested was incubatedwith 1 mL of a buffer mixture of 80% PBS and 20% PEG 400 at 37° C. Foursamples of each formulation to be tested were prepared. At specific timepoints, approximately every day, the PBS:PEG buffer was poured off forpaclitaxel analysis by HPLC, and fresh buffer was added to themicrocentrifuge tube. The release study was terminated at day 26, atwhich point the remaining paclitaxel in the polymer was extracted with asolvent to do a mass balance on paclitaxel.

[0358] The resulting release curves for the release of paclitaxel fromboth polymers are shown in FIG. 18. The total paclitaxel recovery was65% for the P(CHDM-HOP) formulation and 75% for the P(CHDM-EOP)formulation.

Example 51 In Vitro Release of Paclitaxel from P(DAPG-EOP)

[0359] P(DAPG-EOP) microspheres were prepared by a solvent evaporationmethod, using ethyl acetate as the solvent and 0.5% PVA in water as anon-solvent. The resulting microspheres are spherical in shape withparticle sizes ranging from about 20-150 μm, most preferably 20-50 μm.

[0360] The in vitro release of paclitaxel from the microspheres wascarried out in PBS (pH 7.4) at 37° C. To maintain a sink condition, anoctanol layer was placed on top of the PBS to continuously extract thereleased paclitaxel. The released paclitaxel was quantified using anHPLC method, and the in vitro mass loss of the polymer was obtained by agravimetric method. The in vitro release of paclitaxel from themicrospheres was slow and continuous with concomitant polymer mass loss,as shown in FIG. 41.

Example 52 In Vivo Release of Paclitaxel from P(DAPG-EOP)

[0361] P(DAPG-EOP) microspheres were prepared as described above inExample 52, and the In vivo release of paclitaxel from the microsphereswas studied on nude mice. Plasma was collected from each of the testanimals at 1, 14 and 28 days after injection, and paclitaxelconcentration was analyzed by HPLC with MS-MS detection. For efficacystudies, test animals received intraperitoneal injections of a humanovarian cancer cell line OVCAR3 obtained from carrier animals.P(DAPG-EOP) microspheres incorporating paclitaxel or paclitaxel withoutthe biodegradable polymer were also given intraperitoneally at one daypost cell injection. The survival of the animals was also monitored.

[0362] Following a single intraperitoneal administration of themicrospheres, a sustained level of paclitaxel in plasma was obtained forat least 28 days, as shown below in Table 14: TABLE 14 Paclitaxel PlasmaConcentration Paclitaxel Concentration (ng/ml) Paclitaxel Paclitaxel inMicrospheres (125 mg/kg) w/o polymer (120 mg/kg) 1 day 38.98 ± 7.53357.67 ± 136.39 14 days  4.50 ± 1.21 Animal died 28 days  3.98 ± 0.99Animal died

[0363] When a comparable dose of paclitaxel was given intraperitoneally,the nude mice could not tolerate the dose due to the toxicity.

[0364] The biodegradable polymer microsphere delivery system wassurprisingly effective in treating ovarian cancer in the animal modelOVCAR3. As shown in FIG. 42, superior efficacy was obtained, as comparedwith paclitaxel without the biodegradable polymer.

Example 53 Median Survival Data for P(DAPG-EOP) Paclitaxel

[0365] P(DAPG-EOP) microspheres containing 10 mg/kg or 40 mg/kgpaclitaxel were injected into the peritoneums of test animals havingovarian cancer. Other test animals were injected with paclitaxel in anorganic solvent, commercially available under the trade name Taxol, atthe same dosage levels. The test animals were monitored, and mediansurvival times were noted. The results are summarized below: MaterialAdministered Median Survival Control 23 days Taxol, 10 mg/kg 64 daysTaxol, 40 mg/kg 67 days Paclitaxel in 69 days microspheres, 10 mg/kgPaclitaxel in 115 days  microspheres, 40 mg/kg

[0366] These results are represented graphically in FIG. 43 and indicatean unexpectedly large increase in median survival for the test animalsgiven the paclitaxel in the form of biodegradable microspheres.

[0367] A comparison of a different set of dosage levels gave thefollowing similar data: Material Administered Median Survival Control 30days Taxol, 40 mg/kg 77 days Paclitaxel in 83 days microspheres,  4mg/kg Paclitaxel in 95 days microspheres, 10 mg/kg Paclitaxel in >110days  microspheres, 40 mg/kg

[0368] These results are represented graphically in FIG. 44 and confirmthe unexpectedly large increase in median survival for the test animalsgiven the paclitaxel in the form of biodegradable microspheres.Additional graphical representations of this data are provided by FIGS.45 and 46.

[0369] The invention being thus described, it will be obvious that thesame may be varied in many ways. Such variations are not to be regardedas a departure from the spirit and scope of the invention, and all suchmodifications are intended to be included within the scope of thefollowing claims.

I claim:
 1. A biodegradable polymer composition suitable forintraperitoneal administration to treat a mammalian subject havingovarian cancer, said composition comprising: (a) at least oneantineoplastic agent and (b) a biodegradable polymer comprising therecurring monomeric units shown in formula I:

wherein X is —O— or —NR⁴—, where R⁴ is H or alkyl; Y is —O—, —S— or—NR⁴—; each of R¹ and R² is a divalent organic moiety; L is a divalent,branched or straight chain aliphatic group having 1-20 carbon atoms, acycloaliphatic group, or a group having the formula:

R³ is selected from the group consisting of H, alkyl, alkoxy, aryl,aryloxy, heterocyclic or heterocycloxy; and n is about 5-5,000; whereinsaid polymer composition provides extended release of saidantineoplastic agent into the peritoneum of said subject; and whereinsaid polymer composition increases the median survival rate of saidmammalian subject from said cancer by at least about 10%, as comparedwith the median survival rate obtained by administration of acomposition comprising the same dosage of said antineoplastic agentwithout said biodegradable polymer.
 2. The composition of claim 1wherein said polymer composition increases the median survival rate fromsaid cancer by at least about 20%, as compared with the median survivalrate obtained by administration of a composition comprising the samedosage of said antineoplastic agent without said biodegradable polymer.3. The polymer composition of claim 1 wherein said composition increasesthe median survival rate from said cancer by at least about 30%, ascompared with the median survival rate obtained by administration of acomposition comprising the same dosage of said antineoplastic agentwithout said biodegradable polymer.
 4. The polymer composition of claim1 wherein a single dose of said polymer composition provides extendedrelease of said antineoplastic agent over a time of at least 28 days. 5.The polymer composition of claim 1 wherein said polymer is selected fromthe group consisting of:

wherein: M¹ and M² are each independently (1) a branched or straightchain aliphatic group having from 1-20 carbon atoms; or (2) a branchedor straight chain, oxy-, carboxy- or amino-aliphatic group having from1-20 carbon atoms; the molar ratio of x:y is about 1; the molar ration:(x or y) is between about 200:1 and 1:200; and the molar ratio q:r isbetween about 1:99 and 99:1.
 6. A biodegradable polymer compositionsuitable for intraperitoneal administration to treat a mammalian subjecthaving ovarian cancer, said composition comprising: (a) at least oneantineoplastic agent and (b) a biodegradable polymer comprising therecurring monomeric units shown in formula IV:

wherein X is —O— or —NR⁴—, where R⁴ is H or alkyl; Y is —O—, —S— or—NR⁴—; M¹ and M² are each independently (1) a branched or straight chainaliphatic group having from 1-20 carbon atoms; or (2) a branched orstraight chain, oxy-, carboxy- or amino-aliphatic group having from 1-20carbon atoms; L is a divalent, branched or straight chain aliphaticgroup having 1-20 carbon atom; R³ is selected from the group consistingof H, alkyl, alkoxy, aryl, aryloxy, heterocyclic or heterocycloxy; themolar ratio of x:y is about 1; the molar ratio n:(x or y) is betweenabout 200:1 and 1:200; the molar ratio q:r is between about 1:99 and99:1; and n is about 5-5,000; wherein said polymer composition providesextended release of said antineoplastic agent into the peritoneum ofsaid subject; and wherein said composition increases the median survivalrate of said mammalian subject from said cancer by at least about 10%,as compared with the median survival rate obtained by administration ofa composition comprising the same dosage of said antineoplastic agentwithout said biodegradable polymer.
 7. The polymer composition of claim6 wherein a single dose of said polymer composition provides extendedrelease of said antineoplastic agent over a time of at least 28 days. 8.The composition of claim 6 wherein each of M¹, M² and L is a branched orstraight chain alkylene group.
 9. The composition of claim 6 whereineach of M¹, M² and L has from 1 to 7 carbon atoms.
 10. The compositionof claim 6 wherein each of M¹ and M² is an ethylene group or amethyl-substituted methylene group, and L is an ethylene group.
 11. Thecomposition of claim 6 wherein R³ is an alkyl group, an alkoxy group, aphenyl group, a phenoxy group, or a heterocycloxy group.
 12. Thecomposition of claim 6 wherein R³ is an alkoxy group having from 1 to 7carbon atoms.
 13. The composition of claim 6 wherein R³ is an ethoxygroup.
 14. The composition of claim 6 wherein each of M¹ and M² is abranched or straight chain alkylene group.
 15. The composition of claim6 wherein at least one of M¹ and M² is an alkylene or alkoxylene grouphaving a formula selected from the group consisting of —(CH₂)_(a)—,—(CH₂)_(a)—O—, and —(CH₂)_(a)—O—(CH₂)_(b)—, wherein each of a and b isan integer from 1 to
 7. 16. The composition of claim 6 wherein at leastone of M¹ and M² has the formula: —CHR′—CO—O—CHR″—, wherein R′ and R″are each independently H, alkyl, alkoxy, aryl, aryloxy, heterocyclic orheterocycloxy.
 17. The composition of claim 6 wherein each of M¹ and M²has from 1 to 7 carbon atoms.
 18. The composition of claim 6 wherein Xis —O—.
 19. The composition of claim 6 wherein X is —NR⁴—.
 20. Thecomposition of claim 6 wherein: M¹ and M² are each an alkylene oralkoxylene group; L is an alkylene group; X is —O—; and R³ is an alkoxygroup.
 21. The composition of claim 6 wherein the molar ratio x:y isabout
 1. 22. The composition of claim 6 wherein the molar ratio q:r isabout 1:99 and 99:1.
 23. The composition of claim 6 wherein each of xand y is about 1 to 1,000.
 24. The composition of claim 6 wherein themolar ratio n:(x or y) is between about 100:1 and 1:100.
 25. Abiodegradable polymer composition suitable for intraperitonealadministration to treat a mammalian subject having ovarian cancer, saidcomposition comprising: (a) at least one antineoplastic agent and (b) abiodegradable polymer comprising the recurring monomeric units shown informula V:

wherein each of R¹ and R² is independently straight or branchedaliphatic, either unsubstituted or substituted with one or morenon-interfering substituents; L is a divalent cycloaliphatic group; R³is selected from the group consisting of H, alkyl, alkoxy, aryl,aryloxy, heterocyclic or heterocycloxy; and n is about 5-5,000; whereinsaid polymer composition provides extended release of saidantineoplastic agent into the peritoneum of said subject; and whereinsaid composition increases the median survival rate of said mammaliansubject from said cancer by at least about 10%, as compared with themedian survival rate obtained by administration of a compositioncomprising the same dosage of said antineoplastic agent without saidbiodegradable polymer.
 26. The polymer composition of claim 25 wherein asingle dose of said polymer composition provides extended release ofsaid antineoplastic agent over a time of at least 28 days.
 27. Thecomposition of claim 25 wherein each of R¹ and R² is a branched orstraight chain alkylene group having from one to seven carbon atoms. 28.The composition of claim 25 wherein each of R¹ and R² is a methylenegroup or an ethylene group.
 29. The composition of claim 25 wherein R³is an alkoxy group.
 30. The composition of claim 25 wherein R³ ishexyloxy.
 31. The composition of claim 25 wherein n is 5 to
 500. 32. Thecomposition of claim 25 wherein L is a cycloaliphatic group, eitherunsubstituted or substituted with a non-interfering substituent.
 33. Thecomposition of claim 25 wherein L is cyclohexylene.
 34. The compositionof claim 1 wherein said polymer is prepared by solution polymerization.35. The composition of claim 1 wherein said polymer is prepared by meltpolymerization.
 36. The composition of claim 1 wherein said polymercomprises additional biocompatible monomeric units or is blended withother biocompatible polymers.
 37. The composition of claim 1 whereinsaid polymer is soluble in at least one of the solvents selected fromthe group consisting of acetone, dimethylene chloride, chloroform, ethylacetate, DMAC, N-methylpyrrolidone, dimethylformamide anddimethylsulfoxide.
 38. The composition of claim 1 wherein saidantineoplastic agent comprises paclitaxel.
 39. The composition of claim1 wherein the molecular weight (Mw) of said polymer is from about 2,000to 400,000 daltons.
 40. The composition of claim 1 wherein saidantineoplastic agent and said polymer form an amorphous, monolithicmatrix.
 41. The composition of claim 1 in the form of microparticles, aflexible film, a viscous liquid, wafers or rods.
 42. The composition ofclaim 1 in the form of spray-dried microspheres.
 43. The composition ofclaim 1 wherein the composition comprises about 5-15% by weight of theantineoplastic agent.
 44. A biodegradable polymer composition suitablefor intraperitoneal administration to treat a mammalian subject havingovarian cancer, said composition comprising: (a) paclitaxel and (b) abiodegradable polymer comprising the recurring monomeric units shown informula VI:

wherein the molar ratio of x:y is about 1; the molar ratio n:(x or y) isbetween about 200:1 and 1:200; and n is about 5-5,000; wherein saidpolymer composition provides extended release of said antineoplasticagent into the peritoneum of said subject; and wherein said polymercomposition increases the median survival rate of said mammalian subjectfrom said cancer by at least about 10%, as compared with the mediansurvival rate obtained by administration of a composition comprising thesame dosage of said antineoplastic agent without said biodegradablepolymer.
 45. A solid article suitable for insertion into the peritoneumto treat a mammalian subject having ovarian cancer, said articlecomprising a biodegradable polymer composition comprising: (a) at leastone antineoplastic agent and (b) a biodegradable polymer comprising therecurring monomeric units shown in formula I:

wherein X is —O— or —NR⁴—, where R⁴ is H or alkyl; Y is —O—, —S— or—NR⁴—; each of R¹ and R² is a divalent organic moiety; L is a divalent,branched or straight chain aliphatic group having 1-20 carbon atoms, acycloaliphatic group, or a group having the formula:

R³ is selected from the group consisting of H, alkyl, alkoxy, aryl,aryloxy, heterocyclic or heterocycloxy; and n is about 5-5,000; whereinsaid polymer composition provides extended release of saidantineoplastic agent into the peritoneum of said subject; and whereinsaid composition increases the median survival rate of said mammaliansubject from said cancer by at least about 10%, as compared with themedian survival rate obtained by administration of a compositioncomprising the same dosage of said antineoplastic agent without saidbiodegradable polymer.
 46. The article of claim 45 wherein a single doseof said polymer composition provides extended release of saidantineoplastic agent over a time of at least 28 days.
 47. The article ofclaim 45 wherein said composition increases the median survival ratefrom said cancer by at least about 20%, as compared with the mediansurvival rate obtained by administration of a composition comprising thesame dosage of said antineoplastic agent without said biodegradablepolymer.
 48. The article of claim 45 wherein said composition increasesthe median survival rate from said cancer by at least about 30%, ascompared with the median survival rate obtained by administration of acomposition comprising the same dosage of said antineoplastic agentwithout said biodegradable polymer.
 49. The article of claim 45 whereinsaid polymer is selected from the group consisting of:

wherein: M¹ and M² are each independently (1) a branched or straightchain aliphatic group having from 1-20 carbon atoms; or (2) a branchedor straight chain, oxy-, carboxy- or amino-aliphatic group having from1-20 carbon atoms; the molar ratio of x:y is about 1; the molar ration:(x or y) is between about 200:1 and 1:200; and the molar ratio q:r isbetween about 1:99 and 99:1.
 50. A solid article suitable for insertioninto the peritoneum to treat a mammalian subject having ovarian cancer,said article comprising a biodegradable polymer composition suitable forintraperitoneal administration to treat a mammalian subject havingovarian cancer, said composition comprising: (a) at least oneantineoplastic agent and (b) a biodegradable polymer comprising therecurring monomeric units shown in formula IV:

wherein X is —O— or —NR⁴—, where R⁴ is H or alkyl; Y is —O—, —S— or—NR⁴—; M¹ and M² are each independently (1) a branched or straight chainaliphatic group having from 1-20 carbon atoms; or (2) a branched orstraight chain, oxy-, carboxy- or amino-aliphatic group having from 1-20carbon atoms; L is a divalent, branched or straight chain aliphaticgroup having 1-20 carbon atoms; R³ is selected from the group consistingof H, alkyl, alkoxy, aryl, aryloxy, heterocyclic or heterocycloxy; themolar ratio of x:y is about 1; the molar ratio n:(x or y) is betweenabout 200:1 and 1:200; the molar ratio q:r is between about 1:99 and99:1; and n is about 5-5,000; wherein said polymer composition providesextended release of said antineoplastic agent into the peritoneum ofsaid subject; and wherein said composition increases the median survivalrate of said mammalian subject from said cancer by at least about 10%,as compared with the median survival rate obtained by administration ofa composition comprising the same dosage of said antineoplastic agentwithout said biodegradable polymer.
 51. The article of claim 50 whereina single dose of said polymer composition provides extended release ofsaid antineoplastic agent over a time of at least 28 days.
 52. Thearticle of claim 50 wherein each of M¹, M² and L is a branched orstraight chain alkylene group.
 53. The article of claim 50 wherein eachof M¹, M² and L has from 1 to 7 carbon atoms.
 54. The article of claim50 wherein each of M¹ and M² is an ethylene group or amethyl-substituted methylene group, and L is an ethylene group.
 55. Thearticle of claim 50 wherein R³ is an alkyl group, an alkoxy group, aphenyl group, a phenoxy group, or a heterocycloxy group.
 56. The articleof claim 50 wherein R³ is an alkoxy group having from 1 to 7 carbonatoms.
 57. The article of claim 50 wherein R³ is an ethoxy group. 58.The article of claim 50 wherein each of M¹ and M² is a branched orstraight chain alkylene group.
 59. The article of claim 50 wherein atleast one of M¹ and M² is an alkylene or alkoxylene group having aformula selected from the group consisting of —(CH2)_(a)—,—(CH2)_(a)—O—, and —(CH2)_(a)—O—(CH2)_(b)—, wherein each of a and b isan integer from 1 to
 7. 60. The article of claim 50 wherein at least oneof M¹ and M² has the formula: —CHR′—CO—O—CHR″—, wherein R′ and R″ areeach independently H, alkyl, alkoxy, aryl, aryloxy, heterocyclic orheterocycloxy.
 61. The article of claim 50 wherein each of M¹ and M² hasfrom 1 to 7 carbon atoms.
 62. The article of claim 50 wherein X is —O—.63. The article of claim 50 wherein X is —NR⁴—.
 64. The article of claim50 wherein: M¹ and M² are each an alkylene or alkoxylene group; L is analkylene group; X is —O—; and R³ is an alkoxy group.
 65. The article ofclaim 50 wherein the molar ratio x:y is about
 1. 66. The article ofclaim 50 wherein the molar ratio q:r is about 1:99 and 99:1.
 67. Thearticle of claim 50 wherein each of x and y is about 1 to 1,000.
 68. Thearticle of claim 50 wherein the molar ratio n:(x or y) is between about100:1 and 1:100.
 69. A solid article suitable for insertion into theperitoneum to treat a mammalian subject having ovarian cancer, saidarticle comprising a biodegradable polymer composition suitable forintraperitoneal administration to treat a mammalian subject havingovarian cancer, said composition comprising: (a) at least oneantineoplastic agent and (b) a biodegradable polymer comprising therecurring monomeric units shown in formula V:

wherein each of R¹ and R² is independently straight or branchedaliphatic, either unsubstituted or substituted with one or morenon-interfering substituents; L is a divalent cycloaliphatic group; R³is selected from the group consisting of H, alkyl, alkoxy, aryl,aryloxy, heterocyclic or heterocycloxy; and n is about 5-5,000; whereinsaid polymer composition provides extended release of saidantineoplastic agent into the peritoneum of said subject; and whereinsaid composition increases the median survival rate of said mammaliansubject from said cancer by at least about 10%, as compared withthe-median survival rate obtained by administration of a compositioncomprising the same dosage of said antineoplastic agent without saidbiodegradable polymer.
 70. The article of claim 69 wherein a single doseof said polymer composition provides extended release of saidantineoplastic agent over a time of at least 28 days.
 71. The article ofclaim 69 wherein each of R¹ and R² is a branched or straight chainalkylene group having from one to seven carbon atoms.
 72. The article ofclaim 69 wherein each of R¹ and R² is a methylene group or an ethylenegroup.
 73. The article of claim 69 wherein R³ is an alkoxy group. 74.The article of claim 69 wherein R³ is hexyloxy.
 75. The article of claim69 wherein n is 5 to
 500. 76. The article of claim 69 wherein L is acycloaliphatic group, either unsubstituted or substituted with anon-interfering substituent.
 77. The article of claim 69 wherein L iscyclohexylene.
 78. The article of claim 69 wherein said polymer isprepared by solution polymerization.
 79. The article of claim 45 whereinsaid polymer is prepared by melt polymerization.
 80. The article ofclaim 45 wherein said polymer comprises additional biocompatiblemonomeric units or is blended with other biocompatible polymers.
 81. Thearticle of claim 45 wherein said polymer is soluble in at least one ofthe solvents selected from the group consisting of acetone, dimethylenechloride, chloroform, ethyl acetate, DMAC, N-methylpyrrolidone,dimethylformamide and dimethylsulfoxide.
 82. The article of claim 45wherein said antineoplastic agent comprises paclitaxel.
 83. The articleof claim 45 wherein the molecular weight (Mw) of said polymer is fromabout 2,000 to 400,000 daltons.
 84. The article of claim 45 wherein saidantineoplastic agent and said polymer form an amorphous, monolithicmatrix.
 85. The article of claim 45 wherein said antineoplastic agent isencapsulated within said polymer.
 86. The article of claim 45 whereinsaid article results in minimal irritation to non-neoplastic tissueswhen implanted or injected into vasculated tissue.
 87. The article ofclaim 45 wherein said article is in the form of a flexible film, a waferor a rod.
 88. The article of claim 45 wherein said article is in theform of one or more injectable microparticles.
 89. The article of claim45 in the form of spray-dried microspheres.
 90. The article of claim 45wherein the composition comprises about 5-15% by weight of theantineoplastic agent.
 91. A solid article suitable for insertion intothe peritoneum to treat a mammalian subject having ovarian cancer, saidarticle comprising a biodegradable polymer composition suitable forintraperitoneal administration to treat a mammalian subject havingovarian cancer, said composition comprising: (a) paclitaxel and (b) abiodegradable polymer comprising the recurring monomeric units shown informula VI:

wherein the molar ratio of x:y is about 1; the molar ratio n:(x or y) isbetween about 200:1 and 1:200; and n is about 5-5,000; wherein saidpolymer composition provides extended release of said antineoplasticagent into the peritoneum of said subject; and wherein said compositionincreases the median survival rate of said mammalian subject from saidcancer by at least about 10%, as compared with the median survival rateobtained by administration of a composition comprising the same dosageof said antineoplastic agent without said biodegradable polymer.
 92. Amethod for treating a mammalian subject having ovarian cancer, by theextended release of an antineoplastic agent, said method comprising thesteps of: (a) combining the antineoplastic agent with a biodegradablepolymer having the recurring monomeric units shown in formula I:

wherein X is —O— or —NR⁴—, where R⁴ is H or alkyl; Y is —O—, —S— or—NR⁴—; each of R¹ and R² is a divalent organic moiety; L is a divalent,branched or straight chain aliphatic group having 1-20 carbon atoms, acycloaliphatic group, or a group having the formula:

R³ is selected from the group consisting of H, alkyl, alkoxy, aryl,aryloxy, heterocyclic or heterocycloxy; and n is 5-5,000; to form acomposition; and (b) inserting said composition in vivo into theperitoneum of said subject, such that the inserted composition is in atleast partial contact with an ovarian cancer tumor, wherein the mediansurvival rate of said mammalian subject from said cancer is increased byat least about 10%, as compared with the median survival rate obtainedby administration of a composition comprising the same dosage of saidantineoplastic agent without said biodegradable polymer.
 93. The methodof claim 92 wherein a single dose of said polymer composition providesextended release of said antineoplastic agent over a time of at least 28days.
 94. The method of claim 92 wherein said composition increases themedian survival rate from said cancer by at least about 20%, as comparedwith the median survival rate obtained by administration of acomposition comprising the same dosage of said antineoplastic agentwithout said biodegradable polymer.
 95. The method of claim 92 whereinsaid composition increases the median survival rate from said cancer byat least about 30%, as compared with the median survival rate obtainedby administration of a composition comprising the same dosage of saidantineoplastic agent without said biodegradable polymer.
 96. The methodof claim 92 wherein said polymer is selected from the group consistingof:

wherein: M¹ and M² are each independently (1) a branched or straightchain aliphatic group having from 1-20 carbon atoms; or (2) a branchedor straight chain, oxy-, carboxy- or amino-aliphatic group having from1-20 carbon atoms; the molar ratio of x:y is about 1; the molar ration:(x or y) is between about 200:1 and 1:200; and the molar ratio q:r isbetween about 1:99 and 99:1.
 97. A method for treating a mammaliansubject having ovarian cancer, by the extended release of anantineoplastic agent, said method comprising the steps of: (a) combiningthe antineoplastic agent with a biodegradable polymer having therecurring monomeric units shown in formula IV:

wherein X is —O— or —NR⁴—, where R⁴ is H or alkyl; Y is —O—, —S— or—NR⁴—; M¹ and M² are each independently (1) a branched or straight chainaliphatic group having from 1-20 carbon atoms; or (2) a branched orstraight chain, oxy-, carboxy- or amino-aliphatic group having from 1-20carbon atoms; L is a divalent, branched or straight chain aliphaticgroup having 1-20 carbon atom; R³ is selected from the group consistingof H, alkyl, alkoxy, aryl, aryloxy, heterocyclic or heterocycloxy; themolar ratio of x:y is about 1; the molar ratio n:(x or y) is betweenabout 200:1 and 1:200; the molar ratio q:r is between about 1:99 and99:1; and n is about 5-5,000; and (b) inserting said composition in vivointo the peritoneum of said subject, such that the inserted compositionis in at least partial contact with an ovarian cancer tumor, wherein themedian survival rate of said mammalian subject from said cancer isincreased by at least about 10%, as compared with the median survivalrate obtained by administration of a composition comprising the samedosage of said antineoplastic agent without said biodegradable polymer.98. The method of claim 97 wherein a single dose of said polymercomposition provides extended release of said antineoplastic agent overa time of at least 28 days.
 99. The method of claim 97 wherein each ofM¹, M² and L is a branched or straight chain alkylene group.
 100. Themethod of claim 97 wherein each of M¹, M² and L has from 1 to 7 carbonatoms.
 101. The method of claim 97 wherein each of M¹ and M² is anethylene group or a methyl-substituted methylene group, and L is anethylene group.
 102. The method of claim 97 wherein R³ is an alkylgroup, an alkoxy group, a phenyl group, a phenoxy group, or aheterocycloxy group.
 103. The method of claim 97 wherein R³ is an alkoxygroup having from 1 to 7 carbon atoms.
 104. The method of claim 97wherein R³ is an ethoxy group.
 105. The method of claim 97 wherein eachof M¹ and M² is a branched or straight chain alkylene group.
 106. Themethod of claim 97 wherein at least one of M¹ and M² is an alkylene oralkoxylene group having a formula selected from the group consisting of—(CH2)_(a)—, —(CH2)_(a)—O—, and —(CH2)_(a)—O—(CH2)_(b)—, wherein each ofa and b is an integer from 1 to
 7. 107. The method of claim 97 whereinat least one of M¹ and M² has the formula: —CHR′—CO—O—CHR″—, wherein R′and R″ are each independently H, alkyl, alkoxy, aryl, aryloxy,heterocyclic or heterocycloxy.
 108. The method of claim 97 wherein eachof M¹ and M² has from 1 to 7 carbon atoms.
 109. The method of claim 97wherein X is —O—.
 110. The method of claim 97 wherein X is —NR⁴—. 111.The method of claim 97 wherein: M¹ and M² are each an alkylene oralkoxylene group; L is an alkylene group; X is —O—; and R³ is an alkoxygroup.
 112. The method of claim 97 wherein the molar ratio x:y isabout
 1. 113. The method of claim 97 wherein the molar ratio q:r isabout 1:99 and 99:1.
 114. The method of claim 97 wherein each of x and yis about 1 to 1,000.
 115. The method of claim 97 wherein the molar ration:(x or y) is between about 100:1 and 1:100.
 116. A method for treatinga mammalian subject having ovarian cancer, by the extended release of anantineoplastic agent, said method comprising the steps of: (a) combiningthe antineoplastic agent with a biodegradable polymer having themonomeric units shown in formula V:

wherein each of R¹ and R² is independently straight or branchedaliphatic, either unsubstituted or substituted with one or morenon-interfering substituents; L is a divalent cycloaliphatic group; R³is selected from the group consisting of H, alkyl, alkoxy, aryl,aryloxy, heterocyclic or heterocycloxy; and n is about 5-5,000; and (b)inserting said composition in vivo into the peritoneum of said subject,such that the inserted composition is in at least partial contact withan ovarian cancer tumor, wherein the median survival rate of saidmammalian subject from said cancer is increased by at least about 10%,as compared with the median survival rate obtained by administration ofa composition comprising the same dosage of said antineoplastic agentwithout said biodegradable polymer.
 117. The method of claim 116 whereina single dose of said polymer composition provides extended release ofsaid antineoplastic agent over a time of at least 28 days.
 118. Themethod of claim 116 wherein each of R¹ and R² is a branched or straightchain alkylene group having from one to seven carbon atoms.
 119. Themethod of claim 116 wherein each of R¹ and R² is a methylene group or anethylene group.
 120. The method of claim 116 wherein R³ is an alkoxygroup.
 121. The method of claim 116 wherein R³ is hexyloxy.
 122. Themethod of claim 116 wherein n is 5 to
 500. 123. The method of claim 116wherein L is a cycloaliphatic group, either unsubstituted or substitutedwith a non-interfering substituent.
 124. The method of claim 116 whereinL is cyclohexylene.
 125. The method of claim 92 wherein said polymer isprepared by solution polymerization.
 126. The method of claim 92 whereinsaid polymer is prepared by melt polymerization.
 127. The method ofclaim 92 wherein said polymer comprises additional biocompatiblemonomeric units or is blended with other biocompatible polymers. 128.The method of claim 92 wherein said polymer is soluble in at least oneof the solvents selected from the group consisting of acetone,dimethylene chloride, chloroform, ethyl acetate, DMAC,N-methylpyrrolidone, dimethylformamide and dimethylsulfoxide.
 129. Themethod of claim 92 wherein said antineoplastic agent comprisespaclitaxel.
 130. The method of claim 92 wherein the molecular weight(Mw) of said polymer is from about 2,000 to 400,000 daltons.
 131. Themethod of claim 92 wherein said antineoplastic agent and said polymerform an amorphous, monolithic matrix.
 132. The method of claim 92wherein said antineoplastic agent is encapsulated within said polymer.133. The method of claim 92 wherein said article results in minimalirritation to non-neoplastic tissues when implanted or injected intovasculated tissue.
 134. The method of claim 92 wherein said compositionis a viscous liquid.
 135. The method of claim 92 wherein saidcomposition is formed into a shaped, solid article.
 136. The method ofclaim 92 wherein said article is in the form of a flexible film, a waferor a rod.
 137. The method of claim 92 wherein said article is in theform of one or more injectable microparticles.
 138. The method of claim92 wherein the composition comprises about 5-15% by weight of theantineoplastic agent.
 139. A method for treating a mammalian subjecthaving ovarian cancer, by the extended release of paclitaxel, saidmethod comprising the steps of: (a) combining the paclitaxel with abiodegradable polymer having the recurring monomeric units shown informula VI:

wherein the molar ratio of x:y is about 1; the molar ratio n:(x or y) isbetween about 200:1 and 1:200; and n is about 5-5,000; to form acomposition; and (b) inserting said composition in vivo into theperitoneum of said subject, such that the inserted composition is in atleast partial contact with an ovarian cancer tumor, wherein the mediansurvival rate of said mammalian subject from said cancer is increased byat least about 10%, as compared with the median survival rate obtainedby administration of a composition comprising the same dosage of saidantineoplastic agent without said biodegradable polymer.
 140. Thebiodegradable polymer composition of claim 1, wherein the mammaliansubject is a rat or mouse.
 141. The biodegradable polymer composition ofclaim 44, wherein the mammalian subject is a rat or mouse.
 142. Thesolid article of claim 45, wherein the mammalian subject is a rat ormouse.
 143. The solid article of claim 50, wherein the mammalian subjectis a rat or mouse.
 144. The solid article of claim 91, wherein themammalian subject is a rat or mouse.
 145. The method of claim 92,wherein the mammalian subject is a rat or mouse.
 146. The method ofclaim 139, wherein the mammalian subject is a rat or mouse.
 147. Apolymer composition comprising: (a) at least one antineoplastic agentand (b) a biodegradable polymer comprising the recurring monomeric unitsshown in formula I:

wherein X is —O— or —NR⁴—, where R⁴ is H or alkyl; Y is —O—, —S—, or—NR⁴; each of R¹ and R² is a divalent organic moiety; L is a divalent,branched or straight chain aliphatic group having 1-20 carbon atoms, acycloaliphatic group, or a group having the formula:

R³ is selected from the group consisting of H, alkyl, alkoxy, aryl,aryloxy, heterocyclic or heterocycloxy; and n is about 5-5,000; whereinthe polymer composition is suitable for administration to a mammal, andwherein the polymer composition is in at least partial contact with anovarian cancer tumor or the tissue surrounding the site of an ovariancancer tumor.
 148. The polymer composition of claim 147, wherein thecancer tumor has been removed from the site of an ovarian cancer tumor.149. The polymer composition of claim 147, wherein at least oneantineoplastic agent comprises paclitaxel.
 150. The polymer compositionof claim 147, wherein the polymer composition provides extended releaseof at least one antineoplastic agent for at least about four weeks. 151.The polymer composition of claim 150, wherein at least oneantineoplastic agent comprises paclitaxel.
 152. The polymer compositionof claim 150, wherein the polymer composition provides extended releaseof at least one antineoplastic agent for at least about four weeks. 153.The polymer composition of claim 152, wherein at least oneantineoplastic agent comprises paclitaxel.
 154. The polymer compositionof claim 147, wherein said polymer is selected from the group consistingof:

wherein: M¹ and M² are each independently (1) a branched or straightchain aliphatic group having from 1-20 carbon atoms; or (2) a branchedor straight chain, oxy-, carboxy- or amino-aliphatic group having from1-20 carbon atoms; the molar ratio of x:y is about 1; the molar ration:(x or y) is between about 200:1 and 1:200; and the molar ratio q:r isbetween about 1:99 and 99:1.
 155. The polymer composition of claim 147,wherein at least one antineoplastic agent comprises paclitaxel.
 156. Thepolymer composition of claim 147, wherein the polymer compositionprovides extended release of at least one antineoplastic agent for atleast about four weeks.
 157. The polymer composition of claim 156,wherein at least one antineoplastic agent comprises paclitaxel.
 158. Thepolymer composition of claim 154, wherein the cancer tumor has beenremoved from the site of an ovarian cancer tumor.
 159. A biodegradablepolymer composition comprising: (a) at least one antineoplastic agent;and (b) a biodegradable polymer comprising the recurring monomeric unitsshown in formula VII:

wherein the molar ratio of x:y is about 1; the molar ratio n:(x or y) isbetween about 200:1 and 1:200; and n is about 5-5,000; wherein thepolymer composition is suitable for administration to a mammal, andwherein the polymer composition is in at least partial contact with anovarian cancer tumor or the tissue surrounding the site of an ovariancancer tumor.
 160. The polymer composition of claim 159, wherein said atleast one antineoplastic agent comprises paclitaxel.
 161. The polymercomposition of claim 159, wherein the polymer composition providesextended release of at least one antineoplastic agent for at least aboutfour weeks.
 162. The polymer composition of claim 161, wherein at leastone antineoplastic agent comprises paclitaxel.
 163. The polymercomposition of claim 159, wherein the cancer tumor has been removed fromthe site of an ovarian cancer tumor.
 164. The polymer composition ofclaim 160, wherein the cancer tumor has been removed from the site of anovarian cancer tumor.
 165. The polymer composition of claim 161, whereinthe cancer tumor has been removed from the site of an ovarian cancertumor.
 166. The polymer composition of claim 162, wherein the cancertumor has been removed from the site of an ovarian cancer tumor.
 167. Abiodegradable polymer composition comprising: (a) at least oneantineoplastic agent; and (b) the biodegradable polymer shown in formulaVI: VI

wherein the molar ratio of x:y is about 1; the molar ratio n:(x or y) isbetween about 200:1 and 1:200; and n is about 5-5,000; wherein saidpolymer composition is suitable for administration to a mammal; andwherein the polymer composition is in at least partial contact with anovarian cancer tumor or the tissue surrounding the tissue thatsurrounded the site of an ovarian cancer tumor.
 168. The polymercomposition of claim 167, where said at least one antineoplastic agentcomprises paclitaxel.
 169. The polymer composition of claim 167, whereinthe polymer composition provides extended release of said paclitaxel forat least about four weeks.
 170. The polymer composition of claim 169,where said at least one antineoplastic agent comprises paclitaxel. 171.The polymer composition of claim 167, wherein the cancer tumor has beenremoved from the site of an ovarian cancer tumor.
 172. The polymercomposition of claim 168, wherein the cancer tumor has been removed fromthe site of an ovarian cancer tumor.
 173. The polymer composition ofclaim 169, wherein the cancer tumor has been removed from the site of anovarian cancer tumor.
 174. The polymer composition of claim 170, whereinthe cancer tumor has been removed from the site of an ovarian cancertumor.
 175. A solid article comprising a biodegradable polymercomposition comprising: (a) at least one antineoplastic agent and (b) abiodegradable polymer comprising the recurring monomeric units shown informula I:

wherein X is -L- or —NR⁴—, where R⁴ is H or alkyl; Y is —O—, —S— or—NR⁴—; each of R¹ and R² is a divalent organic moiety; L is a divalent,branched or straight chain aliphatic group having 1-20 carbon atoms, acycloaliphatic group, or a group having the formula:

R³ is selected from the group consisting of H, alkyl, alkoxy, aryl,aryloxy, heterocyclic or heterocycloxy; and n is about 5-5,000; whereinthe article is suitable for insertion into a mammal, and wherein thearticle is in at least partial contact with an ovarian cancer tumor orthe tissue surrounding the site of an ovarian cancer tumor.
 176. Thearticle of claim 175, wherein said antineoplastic agent comprisespaclitaxel.
 177. The article of claim 175, wherein the polymercomposition provides extended release of at least one antineoplasticagent for at least about four weeks.
 178. The article of claim 177,wherein at least one antineoplastic agent comprises paclitaxel.
 179. Thearticle of claim 175, wherein the cancer tumor has been removed from thesite of an ovarian cancer tumor.
 180. The article of claim 175, whereinsaid polymer is selected from the group consisting of:

wherein: M¹ and M² are each independently (1) a branched or straightchain aliphatic group having from 1-20 carbon atoms; or (2) a branchedor straight chain, oxy-, carboxy- or amino-aliphatic group having from1-20 carbon atoms; the molar ratio of x:y is about 1; the molar ration:(x or y) is between about 200:1 and 1:200; and the molar ratio q:r isbetween about 1:99 and 99:1.
 181. The article of claim 180, wherein saidantineoplastic agent comprises paclitaxel.
 182. The article of claim180, wherein the polymer composition provides extended release of atleast one antineoplastic agent for at least about four weeks.
 183. Thearticle of claim 182, wherein at least one antineoplastic agentcomprises paclitaxel.
 184. The article of claim 180, wherein the cancertumor has been removed from the site of an ovarian cancer tumor.
 185. Anarticle comprising a biodegradable polymer composition comprising: (a)at least one antineoplastic agent; and (b) a biodegradable polymercomprising a polymer shown in formula VI:

wherein the molar ratio of x:y is about 1; the molar ratio n:(x or y) isbetween about 200:1 and 1:200; and n is about 5-5,000; wherein thearticle is suitable for insertion into a mammal; and wherein the articleis in at least partial contact with an ovarian cancer tumor or, thetissue surrounding the site of an ovarian cancer tumor.
 186. The articleof claim 185, wherein said antineoplastic agent comprises paclitaxel.187. The article of claim 185, wherein the polymer composition providesextended release of at least one antineoplastic agent for at least aboutfour weeks.
 188. The article of claim 187, wherein at least oneantineoplastic agent comprises paclitaxel.
 189. The article of claim185, wherein the cancer tumor has been removed from the site of anovarian cancer tumor.
 190. An article comprising a biodegradable polymercomposition comprising: (a) at least one antineoplastic agent; and (b) abiodegradable polymer comprising the recurring monomeric units shown informula VII:

wherein the molar ratio of x:y is about 1; the molar ratio n:(x or y) isbetween about 200:1 and 1:200; and n is about 5-5,000; wherein thearticle is suitable for insertion into a mammal; and wherein the articleis in at least partial contact with an ovarian cancer tumor or thetissue surrounding the site of an ovarian cancer tumor.
 191. The articleof claim 190, wherein said antineoplastic agent comprises paclitaxel.192. The article of claim 190, wherein the polymer composition providesextended release of at least one antineoplastic agent for at least aboutfour weeks.
 193. The article of claim 192, wherein at least oneantineoplastic agent comprises paclitaxel.
 194. The article of claim190, wherein the cancer tumor has been removed from the site of anovarian cancer tumor.
 195. A biodegradable polymer compositioncomprising: (a) at least one antineoplastic agent; and (b) abiodegradable polymer comprising the recurring monomeric units shown informula IV or V:

wherein: M¹ and M² are each independently (1) a branched or straightchain aliphatic group having from 1-20 carbon atoms; or (2) a branchedor straight chain, oxy-, carboxy- or amino-aliphatic group having from1-20 carbon atoms; the molar ratio of x:y is about 1; the molar ration:(x or y) is between about 200:1 and 1:200; the molar ratio q:r isbetween about 1:99 and 99:1; X is —O— or —NR⁴—, where R⁴ is H or alkyl;Y is —O—, —S— or NR⁴—; each of R¹ and R² is a divalent organic moiety; Lis a divalent, branched or straight chain aliphatic group having 1-20carbon atoms, a cycloaliphatic group, or a group having the formula:

R³ is selected from the group consisting of H, alkyl, alkoxy, aryl,aryloxy, heterocyclic or heterocycloxy; and n is about 5-5,000; whereinthe polymer composition is capable of releasing at least oneantineoplastic agent in a controlled fashion at the site of a ovariancancer tumor or the tissue surrounding the site of an ovarian cancertumor after administration to a mammal.
 196. The polymer composition ofclaim 195, wherein said antineoplastic agent comprises paclitaxel. 197.The polymer composition of claim 195, wherein at least oneantineoplastic is capable of being released for at least four weeks.198. The polymer composition of claim 197, where said antineoplasticagent comprises paclitaxel.
 199. The polymer composition of claim 195,wherein the cancer tumor has been removed from the site of an ovariancancer tumor.
 200. The polymer composition of claim 198, wherein thecancer tumor has been removed from the site of an ovarian cancer tumor.201. A biodegradable polymer composition comprising: (a) at least oneantineoplastic agent; and (b) a biodegradable polymer comprising therecurring monomeric units shown in formula VII:

wherein the molar ratio of x:y is about 1; the molar ratio n:(x or y) isbetween about 200:1 and 1:200; and n is about 5-5,000; wherein thepolymer composition is capable of releasing at least one antineoplasticagent in a controlled fashion at the site of a ovarian cancer tumor orthe tissue surrounding the site of an ovarian cancer tumor afteradministration to a mammal.
 202. The polymer composition of claim 201,wherein at least one antineoplastic agent comprises paclitaxel.
 203. Thepolymer composition of claim 201, wherein at least one antineoplastic iscapable of being released for at least four weeks.
 204. The polymercomposition of claim 203, wherein said antineoplastic agent comprisespaclitaxel.
 205. The polymer composition of claim 201, wherein thecancer tumor has been removed from the site of an ovarian cancer tumor.206. The polymer composition of claim 204, wherein the cancer tumor hasbeen removed from the site of an ovarian cancer tumor.